Question

5-6 a raindrop, as it falls to the ground, reaches a speed known as terminal velocity where the speed of the raindrop is neither increasing nor decreasing. this motion of the raindrop at terminal velocity can be understood in terms of:

a. one vertical force

b. one horizontal force

c. two vertical forces which balance

d. two vertical forces which do not balance

e. two horizontal forces which balance

f. two horizontal forces which do not balance

5-7 in a traffic accident an occupant of the front seat of a car can be thrown through the windshield if he is not wearing a seat belt. which of the following is a correct explanation?

a. the force of impact throws the occupants of the car forward.

b. when you impact, force is backward, so there is an opposite and equal force forward on the occupants.

c. you wont really go through the windshield, they only say that to get you to wear seatbelts.

d. you are not thrown forward, you just keep on moving in the direction you were originally going until something, like the windshield, exerts a backwards force on you

Explanation:

For 5 - 6: When a raindrop reaches terminal velocity, the force of gravity pulling it downwards is balanced by the air - resistance force acting upwards. These are two vertical forces.
For 5 - 7: According to Newton's first law of motion (the law of inertia), an object in motion will stay in motion with the same speed and in the same direction unless acted upon by an unbalanced force. In a car accident, if not wearing a seat - belt, the occupant will continue moving in the direction they were originally moving until the windshield or other objects exert a backward force on them.

Answer:

5 - 6: C. two vertical forces which balance
5 - 7: D. You are not thrown forward, you just keep on moving in the direction you were originally going until something, like the windshield, exerts a backwards force on you.