Encircle the correct answer from given choices.
Newton’s first law of motion is valid only in the absence of:
(a) force (b) net force
(c) friction (d) momentum
Inertia depends on:
(a) force (b) net force
(c) mass (d) velocity
A boy jumps out of a moving bus. There is danger for him to fall:
(a) towards the moving bus (b) away from the bus
(c) in the direction of motion (d) opposite to the direction of motion
A string is stretched by two equal and opposite forces 10N each. The tension in the string is:
(a) zero (b) 5 N
(c) 10 N (d) 20 N
The mass of a body:
(a) decrease when accelerated (b) increase when accelerated
(c) decrease when moving with high velocity(d) none of the above
Two bodies of mass m1 and m2 attached to the ends of an inextensible string passing over a frictionless the dodo pulling such that both move vertically. The acceleration of the bodies is:
(a) (m_1× m_2)/(m_1+ m_2 ) g (b) (m_1- m_2)/(m_1+ m_2 ) g
(c) (m_1+ m_2)/(m_1- m_2 ) g (d) (2m_1 m_2)/(m_1+ m_2 ) g
Which of the following is the unit of momentum?
(a) Nm (b) kgms-2
(c) Ns (d) Ns-2
When horse pulls a cart, the action is on the?
(a) cart (b) earth
(c) horse (d) earth and cart
Which of the following material lowers friction when pushed between metal plates?
(a) water (b) fine marble powder
(c) air (d) oil
Define the following terms:
Inertia
Momentum
Force
Force of friction
Centripetal force
What is the difference between?
Mass and weight
Action and reaction
Sliding friction and rolling friction
georgia aquarium What is the law of inertia?
Why is it dangerous to travel on the roof of a bus?
Why does a passenger move outward when a bus takes a turn?
How can you relate a force with the change of momentum of a body?
What will be the tension in a rope that is pulled from its ends by two opposite forces 100N each?
Action and reaction are always equal and opposite. Then how does a body moves?
A horse pushes the cart. If the action and reaction are equal and opposite then how does the cart move?
What is the law of conservation of momentum?
Why is the law of conservation of momentum important?
When a gun is fired, it recoils. Why?
Describe two situations in which force of friction is needed.
How does oiling the moving parts of a machine lowers friction?
Describe the ways to reduce friction.
Why rolling friction is less then sliding friction?
What do you know about the following:
Tension in a string
Limiting force of friction
Braking force
Skidding of vehicles
Seatbelts
Banking of roads
Cream separator
What would happen if all friction suddenly disappears?
Why the spinner of a washing machine is made to spin at a very high speed?
3.1. A force of 20N moves a body with an
acceleration of 2ms-2, what is its mass?
3.2. The weight of a body is 147N. What is its mass? (Take the value of g as 10ms-2)
3.3. How much force is needed to prevent a body of mass 10kg from falling?
3.4. Find the acceleration by a force of 100N in a mass of 50kg.
3.5. A body has weight 20N. How much force is required to move it vertically upwards with an acceleration of 2ms-2?
3.6. Two masses 52kg and 48 kg are attached to the ends of a string that passes over a frictionless pulley. Find the tension in the string and acceleration in the bodies when both the masses are moving vertically.
3.7. Two masses 26kg and 24kg are attached to the ends of a string marvel's wolverine 2026 release which passes over a frictionless pulley. 26kg is lying over a smooth horizontal table. 24N mass is moving vertically downward. Find the tension in the string and the acceleration in the bodies.
3.8. How much time is required to change 22Ns momentum by a force of 20N?
3.9. How much is the force of friction between a wooden block of mass 5kg and the horizontal marble floor? The coefficient of friction between wood and the marble is 0.6.
3.10. How much centripetal force is needed to make a body of mass 0.5kg to move in a circle of radius of 50cm with a speed of 3ms-1?
