The direction of the ball’s motion remains upward on its way up, but its speed decreases down to zero at the very top of its motion. Throughout the ball’s travel upward and then downward, the acceleration is constant, 9.8m/s2 (the acceleration due to gravity).

What determines the validity of a theory? A theory is supported by scientific evidence and verified by various researchers. A theory predicts certain result which is verified by the experiments or observations.

The Satellite is big enough to be observable by human eyes. The gravitational force on it due to Earth which is weak. So, a satellite moving at a speed of 7500 m/s can be described accurately by Classical Physics.

Is it possible for speed to be constant while acceleration is not zero? Give an example of usch a situation. No, It is not possible. A car moving at a constant speed changing direction.

Answer: It is not possible to have a constant velocity, while the acceleration is not zero, as by definition, Acceleration is rate of change of velocity. 15. Answer: When an object is thrown vertically upwards, at its highest point, the body has a zero velocity, but has an acceleration of ‘g’ in the downward direction.

We should know that during the upward motion, the sign of the position is positive. The sign of the velocity is considered to be negative and the sign of acceleration is positive. Now during the downward motion, the signs of position, velocity and acceleration are all considered to be positive.

Constant velocity means that the object in motion is moving in a straight line at a constant speed. The velocity can be positive or negative, and is indicated by the sign of our slope. This tells us in which direction the object moves.