Question

1.

When the boy throws the ball in to the air, the speed of the ball

A. increases

B. stays the same

C. goes up and then goes down

D. decreases

Answer 1

The speed of ball decreases when it throws in to the air.

Explanation:

Acceleration is the force/mass. The gravitational force is the force acting on an object in free fall. And gravitational force is constant everywhere, and hence for an object with free fall, acceleration will be same. When a ball is threw up in the air, the gravitational force of the body is in the downward direction. The speed of the ball will decreases as it goes higher.Thus, the force acting is,

`\text {Force}=\text {Mass} * \text { (-Gravitational acceleration) }=-m g`

(-Denote the opposite direction of the acting force).

So when a ball is thrown up into the air its speed decreases.