When a carpet is beaten with a stick dust comes out of it. Explain.

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Answer:

When a carpet is beaten with a stick, the carpet becomes in motion, due to inertia, the dust particles want to remain at rest. Due to this the dust particles come out.

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An object of mass 100 kg is accelerated uniformly from a velocity of 5 ms–1 to 8 ms–1 in 6 s. Calculate the initial and final momentum of the object. Also find, the magnitude of the force exerted on the object.

A hockey ball of mass 200 g travelling at 10 ms–1. It struck by a hockey stick so as to return. It along it's original path with a velocity at 5 ms–1. Calculate the change of momentum occurred in the motion of the hockey ball by the force applied by the hockey stick.

According to the third law of motion when we push on an object, the object pushes back on us with an equal and opposite force. If the object is a massive truck parked along the roadside. It will probably not move, A student justifies this by answering that two opposite and equal forces cancel each other comment on this logic and explain why the truck does not move.

Using a horizontal force of 200 N, we intend to move a wooden cabinet across a floor at a constant velocity. What is the friction force that will be exerted on the cabinet?

What is the momentum of an object of mass m, moving with a velocity v ?(a) (mv)2 (b) mv2 (c) 1/2 mv2 (d) mv

An automobile vehicle has a mass of 1500 kg. What must be the force between the vehicle and the road if the vehicle is to be stopped with a negative acceleration of 1.7 ms–2?

A 8000 kg engine pulls a train of 5 wagons each of 2000 kg along a horizontal track. If the engine exerts a force of 40000 N and the track after a friction force of 5000 N then calculate:(a) the net accelerating force.(b) the acceleration of the train, and(c) the force of wagon 1 on wagon 2

A stone of 1 kg is thrown with a velocity of 20 ms–1 across the frozen surface of lake and comes to rest after travelling a distance of 50 m. What is the force of friction between the stone and the ice?

A truck starts from rest and rolls down a hill with a constant acceleration. It travells a distance of 400 m in 20s. Find it's acceleration. Find the force acting on it if it's mass is 7 tonnes (Hint) tonne = 1000 kg)

A batsman hits a cricket ball which then rolls on a level ground. After covering a short distance, the ball comes to rest. The ball slows a stop because: (a)The batsman did not hit the ball hard enough.(b)Velocity is proportional to the force exerted on the ball.(c)These is a force on the ball opposing the motion.(d) These is no unbalanced force on the ball, so the ball would want to come to rest.

Why is it advised to tie any luggage kept on the roof of a bus with a rope?

1. An object experiences a net zero external unbalanced force. Is it possible for the object to be travelling with a non-zero velocity?

Why do you fall in the forward direction when a moving bus brakes to a stop and fall backwards when it accelerates from rest?

Explain why some of the leaves may get detached from a tree if we vigorously shake its branch.

In the following example, try to identify the number of times the velocity of the ball changes: “A football player kicks a football to another player of his team who kicks the football towards the goal. The goalkeeper of the opposite team collects the football and kicks it towards a player of his own team”. Also identify the agent supplying the force in each case.

Which of the following has more inertia: (A)a rubber ball and a stone of the same size? (B)a bicycle and a train? (C)a five rupees coin and a one-rupee coin?

Chapter 8 NCERT Class 9 Science SOLUTIONS

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Chapter 8 NCERT Class 9 Science SOLUTIONS

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More NCERT Questions

An object of mass 100 kg is accelerated uniformly from a velocity of 5 ms–1 to 8 ms–1 in 6 s. Calculate the initial and final momentum of the object. Also find, the magnitude of the force exerted on the object.

An object of mass 100 kg is accelerated uniformly from a velocity of 5 ms–1 to 8 ms–1 in 6 s. Calculate the initial and final momentum of the object. Also find, the magnitude of the force exerted on the object.

A hockey ball of mass 200 g travelling at 10 ms–1. It struck by a hockey stick so as to return. It along it's original path with a velocity at 5 ms–1. Calculate the change of momentum occurred in the motion of the hockey ball by the force applied by the hockey stick.

Using a horizontal force of 200 N, we intend to move a wooden cabinet across a floor at a constant velocity. What is the friction force that will be exerted on the cabinet?

What is the momentum of an object of mass m, moving with a velocity v ?(a) (mv)2 (b) mv2 (c) 1/2 mv2 (d) mv

An automobile vehicle has a mass of 1500 kg. What must be the force between the vehicle and the road if the vehicle is to be stopped with a negative acceleration of 1.7 ms–2?

A 8000 kg engine pulls a train of 5 wagons each of 2000 kg along a horizontal track. If the engine exerts a force of 40000 N and the track after a friction force of 5000 N then calculate:(a) the net accelerating force.(b) the acceleration of the train, and(c) the force of wagon 1 on wagon 2

A stone of 1 kg is thrown with a velocity of 20 ms–1 across the frozen surface of lake and comes to rest after travelling a distance of 50 m. What is the force of friction between the stone and the ice?

A truck starts from rest and rolls down a hill with a constant acceleration. It travells a distance of 400 m in 20s. Find it's acceleration. Find the force acting on it if it's mass is 7 tonnes (Hint) tonne = 1000 kg)

Why is it advised to tie any luggage kept on the roof of a bus with a rope?

1. An object experiences a net zero external unbalanced force. Is it possible for the object to be travelling with a non-zero velocity?

Why do you fall in the forward direction when a moving bus brakes to a stop and fall backwards when it accelerates from rest?

Explain why some of the leaves may get detached from a tree if we vigorously shake its branch.

Which of the following has more inertia: (A)a rubber ball and a stone of the same size? (B)a bicycle and a train? (C)a five rupees coin and a one-rupee coin?

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