Here explain some common effect of force on motion:
A force can cause a stationary object to start moving.
What happens when a stationary football is kicked by a player? It is seen that the ball moves off in the direction it is kicked from its stationary state. In this case the ball accelerates from rest. Here acceleration is positive, and in the same direction as the force exerted by the kick.
A force can cause a moving object to increase its velocity.
What would be the velocity when a cricket ball is hit by the batsman in the same direction as the ball moves? It is observed that the ball moves faster after the hit. In this case the acceleration is positive and its velocity increases. The velocity of a moving marble increases if it is stroked in same direction as it moves.
A force can cause a moving object to decrease speed.
Think you are riding a bicycle in the village road. After a while you observed that the road is slanting downwards. Now what will you do? Will you continue the pedaling as before or give a brake? You have to apply brake to cross this sloping road safely. Due to this, the cycle decelerates.
A force can cause a moving object to change its velocity or direction of motion.
A batsman hits the cricket ball coming from opposite direction during a game of cricket. Due to the hit, the magnitude and direction of the velocity of the ball change. The ball moves in a different direction due to this hit by the bat. In this case too, the ball has acceleration.
