3. What should be the direction of applied
force to decrease the speed of a moving
body? Why? answer in 50 words
Answers
Answer:
If the force applied on the object is in the direction of its motion, the speed of the object increases. If the force is applied in the direction opposite to the direction of motion, then it results in a decrease in the speed of the object.
Answer:
According to law of inertia or Newton's first law of motion, a body in state of rest or of uniform motion remains in state of rest or of uniform motion unless it is acted upon by an external force. Hence a body in uniform motion required no force to keep them in uniform motion.
Given that force = mass x acceleration
Constant speed means there is no acceleration, therefore if acceleration = 0 force is also 0.
So a force is not necessary to maintain constant speed, assuming no friction.
In deep space, for example, objects will zoom along at a constant speed with no force on them whatsoever. That results from Newton's First law of motion, which states a body in motion tends to stay in motion unless acted on by a net force.
But in most cases, when v = constant and it requires a force F to maintain that constant speed, it's because there is a braking force of friction or air drag trying to stop the body from moving. And that's why a push or pull is necessary to maintain a constant speed, to offset those braking forces.