Laws of Motion

Topics in this chapter

• Newton's Laws and Inertia
• Force Analysis and Acceleration
• Friction and Equilibrium
• Connected Bodies and Constraints
• Momentum, Impulse and Collisions
• Circular Motion and Vertical Dynamics

Cheat sheet

Practice questions

1. Question 1Q-BA9910

   A 2 kg block rests on a rough horizontal surface. The coefficient of static friction is 0.4, and g = 10 m/s². If a horizontal force of 6 N is applied to the block, the frictional force on it is

   1. A.0 N
   2. B.6 N
   3. C.8 N
   4. D.20 N
   See the answer and solution
2. Question 2Q-B1E973

   A person of mass 60 kg stands on a weighing machine inside a lift. The lift is accelerating downward with an acceleration of 2 m/s². Taking g = 10 m/s², the reading of the weighing machine is

   1. A.480 N
   2. B.600 N
   3. C.720 N
   4. D.120 N
   See the answer and solution
3. Question 3Q-BCD227

   Two blocks of masses 2 kg and 3 kg are in contact on a smooth horizontal surface. A horizontal force of 10 N is applied to the 3 kg block. What is the contact force exerted by the 3 kg block on the 2 kg block?

   1. A.2 N
   2. B.4 N
   3. C.6 N
   4. D.10 N
   See the answer and solution
4. Question 4Q-CC6767

   A 5 kg block is on a rough inclined plane of angle 37° to the horizontal. The coefficient of static friction is 0.5. A force of 50 N acts on the block parallel to the plane in the upward direction. Given g = 10 m/s², sin 37° = 0.6 and cos 37° = 0.8, the frictional force on the block is

   1. A.0 N
   2. B.10 N downward along the plane
   3. C.20 N downward along the plane
   4. D.50 N downward along the plane
   See the answer and solution
5. Question 5Q-174D67

   A swimmer pushes water backward with his hands and moves forward. Which statement correctly explains this motion?

   1. A.The backward force on water is greater than the forward force on the swimmer.
   2. B.The water exerts a forward force on the swimmer equal in magnitude to the backward force exerted by the swimmer on the water.
   3. C.The swimmer moves forward because no external force acts on him.
   4. D.The forward force on the swimmer is produced by the swimmer's inertia.
   See the answer and solution