Acceleration

A child drops a ball from a window. The ball strikes the ground in $4$ seconds. What is the velocity of the ball the instant before it hits the ground?

How long will it take a car to accelerate from $15.3 \mathrm{m}/\mathrm{s}$ to $24.6 \mathrm{m}/\mathrm{s}$ if the car has an average acceleration of $3.1 \mathrm{m}/{\mathrm{s}}^2$? 

Describe a situation where you can accelerate but the speed doesn’t change.

A body gets decelerated as it moves away from the earth and accelerates as it approaches the earth. Explain.

What do you mean by positive acceleration and negative acceleration? What do they signify?

What is acceleration? Derive the SI units from the definition of acceleration.

Acceleration due to gravity is an example of _____ acceleration.

Acceleration due to gravity on the surface of the earth is _____$\left(9.8/98/0.98\right)$ ${\mathrm{ms}}^{-2}.$

Rate of change in velocity of a body is called _____.

A body that travels with uniform speed still has acceleration.

Bodies fall to the earth as they have mass.

If a body moves $20 \mathrm{m}$ in$1^{st}$ minute, $15 \mathrm{m}$ in $2^{nd}$ minute, it is moving with

When a body is thrown vertically upwards its velocity will

Differentiate between uniform acceleration and variable acceleration.

What do you mean by average velocity of a body? Give the equation and SI unit for average velocity.