First Law of Motion

Q. A ball rolling on ground slows down primarily because of force.

1. frictional
2. gravitational
3. magnetic

Q.

Why are tips and edges of cutting and piercing tools made sharp?

Q.

Why is a sharp knife more effective in cutting fruit than a blunt knife?

Q. Why are heavy bags provided with broad straps?

Q. If the net force on an object in uniform motion is zero, the object will _____.

1. come to rest
2. accelerate non-uniformly
3. accelerate uniformly
4. remains in its state of motion (rest or moving with constant velocity)

Q.

What is dynamics and kindematics?

Q.

State true or false.
The moon's motion around the earth involves first law of motion and uniform motion.

1. True

2. False

Q. Case I: A block of mass 1 kg is placed on a rough horizontal surface.
Case II: A block of mass 1 kg is placed on a rough horizontal surface and another identical block is kept over it.
Choose the correct statement.

1. Static friction acting in case I is greater than that in case II.
2. Static friction acting in case I is less than that in case II.
3. Static friction acting in case I is equal to that in case II and is non-zero.
4. No friction is acting in both cases.

Q.

Which of the following examples can be explained using Newton's first law of motion

1. People in moving bus tend to fall forward if brakes are applied suddenly.

2. Magnets attract each other.

3. When a car takes a sudden turn to the left, objects in it tend to fall outwards.

4. None of these

Q. Why are the edges of the knife and axe kept sharp?

1. Easy to carry
2. Easy to design by a blacksmith
3. For beautification
   
4. Provide more pressure to cut

Q.

What is Meant by Inertia?

Q. Choose the incorrect statement from the following:

1. Fluid friction depends on the shape of the moving object.
2. Fluid friction always opposes the relative motion.
3. Fluid friction does not depend on the nature of the medium.
4. Fluid friction increases with an increase in relative speed.

Q.

Is a force required to keep a body moving

Q. An object at rest does not move upon pushing if an external force is opposing the applied force.

1. True
2. False

Q. A moving object will continue to be in motion unless stopped by external forces.

1. True
2. False

Q.

On what factors does the friction on an object depends in a fluid? [3 MARKS]

Q. The rate of change of velocity moving opposite to the direction of motion is called deceleration.

1. True
2. False

Q. An object resists any change in it's state of motion, unless compelled to change by an external force acting on it.

1. True
2. False

Q.

The natural tendency of objects is to resist a change in their state of rest or uniform motion. The resistance to change of state of motion or rest is termed as ___.

Q. When a ball is thrown upwards, its speed decreases. It means that:

1. Force is acting on the ball downwards.
2. Force is acting on the ball upwards.
3. Force is acting on the ball sideways.
4. No force is acting on the ball.

Q. If there were no forces acting on it, a sliding object would continue to slide forever.

1. True
2. False

Q. If a block is sliding at a speed of 2 m/s on rough ground, friction will act on it.

1. no
2. static
3. sliding

Q. A man spinning in free space changes the shape of his body, e.g., by spreading his arms or curling up. By doing this, he can change his :

1. moment of inertia.
2. angular momentum.
3. angular velocity.
4. rotational kinetic energy.

Q. A moving object will continue to be in motion unless stopped by external forces.

1. False
2. True

Q. A moving object will continue to be in motion unless stopped by external forces.

1. True
2. False

Q.

What are the characterstics of rotaional movement

Q. A moving object will continue to be in motion unless stopped by external forces.

1. True
2. False

Q. Explain the following:
a. Why can't we hammer a nail by its head on the wood?
b. A sharp knife cuts better than a blunt knife.

Q.

Newton's first law of motion can also be referred to as

1. Law of inertia

2. Law of forces

3. Law of momentum

4. None of these

Q. The rate of change of velocity moving opposite to the direction of motion is called deceleration.

1. False
2. True