Laws of Motion and momentum

Which one of the following has the same unit as the rate of change of momentum?

• work
• energy
• acceleration
• weight

The graph shows how the resultant force applied to an object of mass 2.0 kg, initially at rest, varies with time.
What is the speed of the object after 1.0 s?  

• 2.5 m s⁻¹
• 5.0 m s⁻¹
• 7.5 m s⁻¹
• 10 m s⁻¹

.An object is accelerated from rest by a constant force F for a time t. Which graphs represent the variation of time with the change in the kinetic energy and the change in momentum of the object?

• A
• B
• C
• D

What is represented by the area under a force–displacement graph?

• rate of change of kinetic energy
• change in momentum
• work done
• acceleration

In a test a 500 kg car travelling at 10 m s^–1 hits a wall. The front 0.30 m of the car crumples as the car is brought to rest. What is the average force on the car during the impact?

• 830 N
• 7500N
• 8300N
• 83 000N

.The nucleus of a radioactive isotope X is at rest and decays by emitting an α particle so that a new nuclide Y is formed. Which one of the following statements about the decay is correct?

• The momentum of Y is equal and opposite to the momentum of the α particle
• The momentum of Y is equal to the momentum of X.
• The kinetic energy of Y is equal to the kinetic energy of the α particle.
• The total kinetic energy is the same before and after the decay.

Which line, A to D, in the table correctly shows what is conserved in an elastic collision?

• A
• B
• C
• D

Trolley T₁, of mass 2.0 kg, collides on a horizontal surface with trolley T₂, which is also of mass 2.0 kg. The collision is elastic. Before the collision T₁ was moving at 4.0 m s^–1 and T₂ was at rest. Which one of the following statements is correct? Immediately after the collision

• T₁ is at rest and T₂ moves at 4.0 m s^–1.
• T₁ will rebound from T₂ at 4.0 m s^–1.
• T₁ and T₂ will both move at 2.8 m s^–1.
• T₁ and T₂ will both move at 1.4 m s^–1.

The graph shows how the resultant force applied to an object of mass 2.0 kg, initially at rest, varies with time.
What is the speed of the object after 1.0 s?  

• 2.5 m s⁻¹
• 5.0 m s⁻¹
• 7.5 m s⁻¹
• 10 m s⁻¹

.An object is accelerated from rest by a constant force F for a time t. Which graphs represent the variation of time with the change in the kinetic energy and the change in momentum of the object?

• A
• B
• C
• D