Sam wants to modify the formula for acceleration
I.e., a = (v – u)/ t
Where v = final velocity, u = initial velocity, t= time, a = acceleration, to suit the special case of freefall of a ball dropped from the top of a building. He chooses to make the following substitutions in the formula.
a. v= 0
b. u= 0
c. a= 9.8 m/s²
Identify the correct substitutions.

A monkey falls from the top of a tall tree reaches a velocity of ___ m/s in 20 s.

A body moves in such a way that its velocity increases by 4 m/s every second. Its acceleration is ___ m/s².

What is the acceleration of a truck which starts from rest, and after 5 s its velocity is 20 m/s? What is the direction of the acceleration of the truck?

Acceleration is a _____ quantity, as it has ____.

In positive acceleration its magnitude will be positive and direction is same as of the velocity. 
In negative acceleration its magnitude will be negative and direction is opposite as of the velocity.

A car moves at a speed of 5 m/s throughout its journey. What is its acceleration?

the car is not speeding up or slowing down.

A car moving at a velocity of 6.5 m/s increases its velocity uniformly to 78 m/s in 10 s. Work out its acceleration with a proper sign.

Positive acceleration means the direction of acceleration is same as of the direction of velocity.

Pick the odd one out.

The following table shows the velocity of a moving car at different timestamps. The car is undergoing ___.

Timestamp	Velocity in m/s
11:00	34
11:05	32
11:10	27
11:15	18
11:20	24
11:25	43
11:30	49

Acceleration is the rate of change of velocity.

Which of the following is/are true for a freefall?
a. It is a uniform motion in which an object falls towards the center of the earth.
b. It is an accelerated, non-uniform motion in which an object falls towards the center of the earth.
c. It is a uniformly accelerated motion.
d. The acceleration due to gravity is 9.8 m/s².

Which of the following remains constant in a uniform circular motion?

Which of the following is/are true for a uniform circular motion?
a. It is an accelerated motion.
b. The speed of the body keeps on constantly changing throughout the motion.
c. The velocity of the body keeps constantly changing throughout the motion.
d. The acceleration of the body is directed along with the velocity at all points of motion.

What is the direction of positive acceleration w.r.t. the velocity of a moving body?

A moving body is said to be decelerating if it is ____.

A moving body is said to be positively accelerating if it is ____.

Example : when person jumps off the height.

Which of the following remains constant during freefall?