EJU - Examination for Japanese University Physics: Mechanics and Energy Questions and Answers

Question 1

A 2 kg object, initially at rest on a frictionless horizontal surface, is subjected to a constant horizontal force of 10 N. What is the kinetic energy of the object after it has been displaced by 4 m?

Accepted Answer

40 J

Answer

20 J

Answer

80 J

Answer

10 J

Question 2

A simple pendulum with a 0.5 kg bob is released from rest at a height 'h' above its lowest point. If its speed at the lowest point is 2 m/s, what is the initial height 'h'? (Assume g = 10 m/s² and neglect air resistance).

Accepted Answer

0.2 m

Answer

0.4 m

Answer

0.1 m

Answer

0.5 m

Question 3

A 4 kg cart moving at 5 m/s collides with a 6 kg cart that is initially at rest. The two carts stick together after the collision. What is their common velocity after the collision?

Accepted Answer

2 m/s

Answer

3 m/s

Answer

5 m/s

Answer

2.5 m/s

Question 4

An object is launched with an initial velocity at an angle to the horizontal. Neglecting air resistance, which of the following quantities is zero when the object reaches the highest point of its trajectory?

Accepted Answer

The vertical component of its velocity

Answer

The horizontal component of its velocity

Answer

Its acceleration

Answer

The horizontal component of its acceleration

Question 5

A 5 kg box is pulled across a horizontal floor by a force of 40 N. The coefficient of kinetic friction between the box and the floor is 0.3. What is the net work done on the box if it is moved a distance of 10 m? (Use g = 10 m/s²).

Accepted Answer

250 J

Answer

400 J

Answer

150 J

Answer

550 J

Question 6

For an object undergoing uniform circular motion at a constant speed, which of the following statements is correct?

Accepted Answer

Its acceleration vector is directed towards the center of the circle.

Answer

Its velocity is constant.

Answer

Its acceleration is directed tangent to the circle.

Answer

Its acceleration is zero because its speed is constant.

A 2 kg object, initially at rest on a frictionless horizontal surface, is subjected to a constant horizontal force of 10 N.What is the kinetic energy of the object after it has been displaced by 4 m?

A 2 kg object, initially at rest on a frictionless horizontal surface, is subjected to a constant horizontal force of 10 N.
What is the kinetic energy of the object after it has been displaced by 4 m?