An object accelerates (changes its speed) only if the forces acting on it in one direction are greater than the forces in the opposite direction, All of the following objects will accelerate EXCEPT?


A) a ball striking a wall, in which the force of the ball on the wall is equal to the force of the wall on the ball
B) a gas balloon in which the buoyant force is greater than its weight and air resistance
C) a man in a parachute when the air resistance is less than his weight
D) an airplane in horizontal flight when the thrust of the engine is equal to the drag of the air

assistance needed

Please type your subject in the School Subject box. Any other words are likely to delay responses from a teacher who knows that subject well.

The momentum of the ball changed when it struck the wall. It accelerated.

To determine which of the objects will not accelerate, we need to identify cases where the net force on the object is zero or balanced force.

A) In the case of a ball striking a wall, if the force of the ball on the wall is equal to the force of the wall on the ball, the net force on the ball is zero. Therefore, it will not accelerate.

B) In the case of a gas balloon, if the buoyant force is greater than its weight and air resistance, there will be a net upward force. Since the net force is not zero but in the upward direction, the balloon will accelerate upward.

C) In the case of a man in a parachute, if the air resistance is less than his weight, there will be a net downward force. Therefore, the man will accelerate downward.

D) In the case of an airplane in horizontal flight, if the thrust of the engine is equal to the drag of the air, the net force on the airplane is zero. Hence, it will not accelerate.

Therefore, the correct answer is option A) a ball striking a wall, in which the force of the ball on the wall is equal to the force of the wall on the ball.