Question

When an object is thrown up, the force of gravity
A. Acts in the direction of the motion
B. Acts in the opposite direction of the motion
C. Decreases as the body move up
D. Increases as the body move up

Answer 1

All objects when thrown on the earth's surface, it comes back to the earth due to its force of gravitation on the surface. The surface of the earth is considered as zero levels and the value rises as it moves upward which can be either position or velocity. Gravity always acts downward.

Complete step by step solution:
Once the body is thrown upwards, it goes up until the velocity of the ball turns out to be zero and the force exerted on it becomes zero. After that, the ball touches the ground with acceleration due to gravity and zero velocity. When the ball goes up, the height of the ball rises and it also moves up. So the position becomes positive. The ball moves up with some velocity attained by the force applied by the person who throws the ball. This is restricted until the ball force of the ball is zero. However the velocity of the ball when moving up reduces, the direction is upward. Therefore the velocity of the ball is also positive. The acceleration that acts on the body is because of the gravitational force. The acceleration due to gravity is downwards in the direction of the surface of the earth. Hence in this situation, the downward is measured as positive and the upward is measured as negative. As the acceleration moves the ball up against the force of gravity, it becomes negative.
So the right answer is in option (B).

Note:
If we take one example of this case. During the launching process of a rocket, it moves up consuming the fuel in it. The force is delivered by the fuel to go up until it surpasses the earth’s gravitational force. This velocity of the rocket is known as the escaping velocity.