Challenge Problems! >.< As they say in my worksheet.

Question

I dont knw how to solve them. So please help me. I dont have tutors yet so thank you so much if you could answer these.

1. An arrow leaves a bow with a speed of 42m/s. Its velocity is reduced to 34 m/s by the time it hits the target. How much distance did the arrow travel over if it were in the air for 2.4 seconds?

2. At a drag race, a jet car travels 1/4 mile in 5.2 seconds. What is the final speed of the car and its acceleration?

3. A person taps his finger repeatedly. Their finger travels 2.5 cm before making contact with the table top. The finger tapping noise is heard once every 0.20 seconds. What is the impact speed of the finger with the table?

Thxxx so MUCH!!!!

Answer 1

I think you should do your own homework.

1) The distance travelled assuming a constant (linear) rate of speed loss is : The initial distance (zero in this case) plus initial velocity x time plus a half times the acceleration x time squared.

Acceleration in this case is a negative quantity or a deceleration. It is equal to the change in velocity divided by change in time.

You do the rest. If you study the explanation you will be able to understand it and apply it to the second question.

The last question sux. You have to make an assumption about how much time the finger spends going up, and that the downward movement is at constant acceleration. Neither is a good assumption, except it makes the physics simple.

good luck.