Daily Practice Problems

Class 9 Science

Motion

Class 9 Science

Motion

**Question 1:**

Suppose a boy is enjoying a ride on a merry-go-round which is moving with a constant speed of 10 m/s. what does it implies with respect to boy?

(a) at rest

(b) moving with no acceleration

(c) in accelerated motion

(d) moving with uniform velocity

**Question 2:**

If the displacement of an object is proportional to square of time, then the object moves with

(a) uniform velocity

(b) uniform acceleration

(c) increasing acceleration

(d) decreasing acceleration

**Question 3: **

A body is thrown vertically upward with velocity u, the greatest height h to which it will rise is,

(a) u/g

(b) u^{2}/2g

(c) u^{2}/g

(d) u/2g

**Question 4:**

In which of the following cases of motions, the distance moved and the magnitude of displacement are equal?

(a) If the car is moving on straight road

(b) If the car is moving in circular path

(c) The pendulum is moving to and fro

(d) The earth is revolving around the Sun

**Question 5:**

The maximum speed of a train is 80 km/h. It takes 10 h to cover a distance of 400 km. Find the ration of its maximum speed to its average speed.

**Question 6:**

Starting from a stationary position, Rahul paddles his bicycle to attain a velocity of 6 m s^{–1} in 30 s. Then he applies brakes such that the velocity of the bicycle comes down to 4 m s^{-1} in the next 5 s. Calculate the acceleration of the bicycle in both the cases.

**Question 7:**

The brakes applied to a car produce an acceleration of 6 m s^{-2} in the opposite direction to the motion. If the car takes 2 s to stop after the application of brakes, calculate the distance it travels during this time.

**Question 8:**

What are inertial and non-inertial frames of reference?

**Question 9:**

Write some uses of velocity- time graph?

**Question 10:**

A stone is thrown in a vertically upward direction with a velocity of 5 m s^{-1}. If the acceleration of the stone during its motion is 10 m s^{–2 }in the downward direction, what will be the height attained by the stone and how much time will it take to reach there?

**Question 11:**

Give an example of a body which may appear to be moving for one person and stationary for the other.

**Question 12:**

What can you say about the motion of an object if its speedtime graph is a straight line parallel to the time axis?

**Question 13:**

A body starting from rest has an acceleration of 4 m/s^{2}. Calculate distance travelled by it in 5^{th} second.

**Question 14:**

Differentiate between distance and displacement.

**Question 15:**

Derive 1^{st} equation of motion graphically?

**Question 16:**

Derive 2^{nd} equation of motion graphically?

**Question 17:**

Derive 3^{rd} equation of motion graphically?

**Question 18:**

What is the nature of the distance-time graphs for uniform and non-uniform motion of an object?

**Question 19:**

A racing car has a uniform acceleration of 4 m s^{-2}. What distance will it cover in 10 s after start?

**Question 20:**

How can we describe the location of the object?

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