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Parachutes are used to slow down a certain racing car.

Figure 1 shows the racing car, of total mass 750 kg, slowing down by using parachutes.

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Figure 2 is the speed-time graph  20 s after the car reaches full speed.

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At the timet=60 s, the parachutes open.

(a) In Fig 1 

   (i) mark a point, labelled A, where the car is moving at a constant speed.

   (ii) mark a point, labelled B, where the car is decelerating at a uniform rate.

   (iii) mark a point, labelled C, where the car is decelerating at a non-uniform rate.

(b) Calculate

   (i) the deceleration of the car at the time t=6.5 s.

   (ii) the resultant force acting on the car at this time.

(c) Explain why there is no resultant force acting on the car at the time t=4.0 s

Important Questions on Equations of Motion

MEDIUM

A body starts from rest is accelerated uniformly for 30s. If x1, x2, x3 are the distances travelled in first 10s; next 10s and last 10s respectively, then x1 : x2 : x3 is

EASY

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In the above graph what is the value of acceleration? 

MEDIUM
A car accelerates uniformly from 18 km/h to 36 kmh in 5 sec. Calculate the acceleration.
MEDIUM
A train starting from rest attains velocity of 72 km h-1 in 5 min, then find the acceleration.
(Assuming that the acceleration is uniform)
EASY
Two particles A and B having different masses are projected from a tower with same speed. A is project vertically upward and B vertically downward. On reaching the ground
EASY

Can we use equations of motion for motion having variable acceleration?

EASY

State which of the following situations are possible and give an example for each of these:

An object with a constant acceleration but with zero velocity.

EASY
What is the acceleration of a body moving with uniform velocity?
EASY
Which of these is not an example of non-uniform acceleration?
EASY

State whether the following situation is possible and give an example for it: An object with a constant acceleration but with zero velocity.

MEDIUM
What do we mean by saying that the acceleration of a body is 3 m s-2?
MEDIUM

Give an example of each.

(i) acceleration is in the direction of motion.

(ii) acceleration is against the direction of motion.

(iii) acceleration is uniform.

(iv) acceleration is non-uniform.

EASY
Acceleration is a vector quantity, which indicates that its value ____________ .
MEDIUM
A ball is gently dropped from a height of 20 m. If its velocity increases uniformly at the rate of 10 m s-2. With what velocity will it strike the ground? After what time will it strike the ground?
MEDIUM

State whether the following situation is possible or not and give an example for the case.

An object with a constant acceleration but with zero velocity.

EASY

What do you mean by 5 m s-2?

EASY
What does negative slope of velocity-time graph represent?
EASY

Equations of motion are used for uniformly accelerated motion only. Comment​

EASY

Can be a body be accelerated, if it is moving with constant speed?

EASY

When do we say that a body is retarding or decelerating?