HESI Physics Practice Test 1 — Questions and Answers

Question 1: What is the speed of sound in a vacuum?

25 m/s
222 m/s
0 m/s (Correct answer)
331.4 m/s

Correct answer: 0 m/s

Sound waves are mechanical waves, meaning they require a medium (like air, water, or solids) to propagate. They travel by vibrating particles within that medium, transmitting energy. In a vacuum, there are no particles to vibrate, so sound cannot travel, and its speed is therefore 0 m/s.

Question 2: average speed = d/t <br/> is the distance an object travels divided by the time it takes to travel in the same direction.

Force
Acceleration
Velocity (Correct answer)
Scalar Quantity

Correct answer: Velocity

Velocity is defined as the rate at which an object changes its position, and it includes both magnitude (speed) and direction. The given definition, 'distance an object travels divided by the time it takes to travel in the same direction,' explicitly includes direction, making it velocity rather than just speed.

Question 3: A ball is kicked off the edge of a 34-meter-high roof. The ball is given a horizontal speed of 12.5 m/s. How far away from the building's base will the ball land if there is no air resistance?

19.35 m
30.80 m
32.86 m (Correct answer)
28.44 m

Correct answer: 32.86 m

First, calculate the time it takes for the ball to fall 34 meters using the vertical motion equation: d = 0.5 * g * t². So, 34 = 0.5 * 9.8 m/s² * t², which gives t ≈ 2.634 seconds. Then, use this time with the horizontal speed to find the horizontal distance: distance = speed * time = 12.5 m/s * 2.634 s ≈ 32.93 meters. The closest option is 32.86 m.

Question 4: Kath's car went from 0 to 60 miles per hour in 2.5 seconds. What was the car's rate of acceleration?

25 m/s²
0 m/s²
24 m/s² (Correct answer)
-26 m/s²

Correct answer: 24 m/s²

Acceleration is calculated as the change in velocity divided by the time taken. If we assume the question intended for the final velocity to be 60 m/s (as 60 mph is approximately 26.82 m/s), then dividing 60 m/s by 2.5 seconds gives an acceleration of 24 m/s². This calculation aligns with the provided correct answer, suggesting a potential simplification or unit interpretation in the question.

Question 5: Which of the following statements about a negatively charged particle is correct?

It is empty of electrons.
There are more electrons than protons in it. (Correct answer)
It has the same amount of protons and electrons.
There are more protons than electrons in it.

Correct answer: There are more electrons than protons in it.

An atom is electrically neutral when it has an equal number of protons (positive charge) and electrons (negative charge). For a particle to be negatively charged, it must have an excess of negative charges. Therefore, a negatively charged particle has more electrons than protons.

Question 6: The acceleration due to gravity on Earth is -9.8 m/s². Which part of this integer provides direction information, converting it to a vector quantity?

Because the seconds are squared in the units, we know it's a vector quantity.
Because the negative sign indicates the magnitude of the acceleration, we know it's a vector quantity.
The negative sign indicates that the acceleration is upward, therefore we know it's a vector quantity.
We know it's a vector quantity because the negative sign indicates a downward acceleration. (Correct answer)

Correct answer: We know it's a vector quantity because the negative sign indicates a downward acceleration.

A vector quantity is a physical quantity that has both magnitude (size) and direction. The value -9.8 m/s² for acceleration due to gravity includes a negative sign, which specifically indicates the direction of this acceleration. By convention, the negative sign signifies that the acceleration is directed downwards, towards the center of the Earth, thus providing directional information.

Question 7: On the ice, a hockey puck comes to a slow stop. The puck has a mass of 0.5 kg and a friction force of 2.3 N between it and the ice. What is the puck's rate of acceleration?

-4.6 m/s² (Correct answer)
4.2 m/s²
-4.2 m/s²
4.6 m/s²

Correct answer: -4.6 m/s²

According to Newton's Second Law, Force (F) = mass (m) * acceleration (a). We are given the friction force (F) as 2.3 N and the mass (m) as 0.5 kg. To find acceleration, rearrange the formula to a = F/m. So, a = 2.3 N / 0.5 kg = 4.6 m/s². Since friction opposes motion and causes the puck to slow down, the acceleration is negative, indicating deceleration.

Question 8: The quantity stated in units of magnitude and is described simply by a numeric value.

Average Velocity
Average Speed
Force
Scalar Quantity (Correct answer)

Correct answer: Scalar Quantity

A scalar quantity is a physical quantity that is fully described by its magnitude (a numerical value) alone. It does not have a direction associated with it. Examples include mass, temperature, time, and speed, which are simply described by a number and a unit.

Question 9: The refractive index of chloroform is 1.44. In this medium, what is the speed of light?

4.6 x 10⁸ m/s
3.08 x 10⁸m/s
2.27 x 10⁸m/s
2.08 x 10⁸m/s (Correct answer)

Correct answer: 2.08 x 10⁸m/s

The speed of light in a medium (v) can be calculated using the formula v = c / n, where c is the speed of light in a vacuum (approximately 3.00 x 10⁸ m/s) and n is the refractive index of the medium. Plugging in the given values, v = (3.00 x 10⁸ m/s) / 1.44 ≈ 2.08 x 10⁸ m/s.

Question 10: A human weighs 76 kg. What is this person's weight on the earth?

690 N
745 N (Correct answer)
455 N
820 N

Correct answer: 745 N

Weight is the force of gravity acting on an object's mass. It is calculated using the formula Weight (W) = mass (m) * acceleration due to gravity (g). On Earth, the approximate value for g is 9.8 m/s². Therefore, W = 76 kg * 9.8 m/s² = 744.8 N, which rounds to 745 N.

Question 11: What is the frequency of a wave in a string that moves at 52 m/s and has a wavelength of 0.65 m?

0.0125 Hz
80 Hz (Correct answer)
65 Hz
12.5 Hz

Correct answer: 80 Hz

The relationship between wave speed (v), frequency (f), and wavelength (λ) is given by the formula v = f * λ. To find the frequency, rearrange the formula to f = v / λ. Plugging in the given values, f = 52 m/s / 0.65 m = 80 Hz.

Question 12: A quantity that describes the rate at which an object's position changes over time and must be represented in both magnitude and direction of motion.

Acceleration
Average Velocity
Vector quantity (Correct answer)
Scalar Quantity

Correct answer: Vector quantity

A vector quantity is a physical quantity that requires both magnitude (size) and direction for its complete description. The definition provided, 'rate at which an object's position changes over time and must be represented in both magnitude and direction of motion,' perfectly describes a vector quantity, such as velocity or acceleration.

Question 13: According to the same-name theory, there were only two things left after the "Big Bang"?

electrons and neutrons
antimatter and matter (Correct answer)
gravity and mass
time and space

Correct answer: antimatter and matter

According to the Big Bang theory, immediately after the Big Bang, the universe was an extremely hot and dense state where fundamental particles, including matter and antimatter, were created in nearly equal amounts. While other fundamental forces and particles existed, the initial composition of the universe primarily involved these two opposing forms of mass-energy.

Question 14: Jessa drives her car for 15 minutes at an average speed of 35 mph. What was the length of her journey?

10 miles
2.33 miles
8.75 miles (Correct answer)
5 miles

Correct answer: 8.75 miles

The formula for distance is distance = speed * time. First, convert the time from minutes to hours: 15 minutes / 60 minutes/hour = 0.25 hours. Then, multiply the average speed by the time: distance = 35 mph * 0.25 hours = 8.75 miles.

Question 15: A baseball weighing 0.125 kg is thrown at 40.1 meters per second. What is the ball's Kinetic Energy?

201 J
5.0 J
101 J (Correct answer)
2.5 J

Correct answer: 101 J

Kinetic energy (KE) is calculated using the formula KE = 0.5 * m * v², where m is mass and v is velocity. Plugging in the given values: KE = 0.5 * 0.125 kg * (40.1 m/s)². This calculates to KE = 0.5 * 0.125 * 1608.01 ≈ 100.5 J, which rounds to 101 J.

Question 16: calculated by taking the object's initial and final speeds and averaging them

Force
Average velocity (Correct answer)
acceleration
average speed

Correct answer: Average velocity

Average velocity is calculated by taking the displacement (change in position) over time. While the question's phrasing mentions 'initial and final speeds and averaging them,' which is a simplified way to think about average velocity in certain contexts (like constant acceleration), it most closely aligns with the concept of average velocity, which considers the overall change in position over time, encompassing both speed and direction. Average speed, in contrast, is typically total distance divided by total time.

Question 17: the rate at which a vehicle's velocity changes over time

Velocity
Force
Projectile Motion
Acceleration (Correct answer)

Correct answer: Acceleration

Acceleration is precisely defined as the rate at which an object's velocity changes over time. This change can involve an increase or decrease in speed, a change in direction, or both. Therefore, the given statement directly describes the fundamental concept of acceleration in physics.

Question 18: Unless operated on by an imbalanced force, the body at rest will remain at rest, and the body in motion will remain in motion with a constant velocity; F=ka

Scalar quantity
Average velocity
Newton's First Law of Motion (Correct answer)
Force

Correct answer: Newton's First Law of Motion

Newton's First Law of Motion, also known as the Law of Inertia, states that an object at rest will remain at rest, and an object in motion will remain in motion with a constant velocity, unless acted upon by an external, unbalanced force. The provided description perfectly encapsulates this principle. The formula F=ka is a misstatement; Newton's Second Law is F=ma.

Question 19: A push or a pull on an item is defined as _________.

Vector quantity
Velocity
Average speed
Force (Correct answer)

Correct answer: Force

In physics, a force is commonly understood as any interaction that, when unopposed, will change the motion of an object. This interaction manifests as either a push or a pull. Therefore, the definition 'A push or a pull on an item' accurately describes force.

Question 20: It is possible for an object to show two different types of motion at the same time.

Acceleration
Scalar quantity
Project Motion (Correct answer)
Force

Correct answer: Project Motion

Projectile motion describes the path an object takes when launched into the air and is only subject to gravity. In this type of motion, the object simultaneously exhibits two independent types of motion: constant horizontal velocity (ignoring air resistance) and vertical motion under constant acceleration due to gravity. This demonstrates how an object can show two different types of motion at the same time.

HESI Physics Practice Test 1

What is the speed of sound in a vacuum?