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**Question 1:**

At what speed must you go over a speed bump if people in your car are to feel weightless?

car speed V=12m/s

bump radius 35m

I don't know how to approch this problem. please help?

**Question2:**

A 0.075kg toy airplane if tied to the ceiling with a string. When the airplane's motor is started, it moves with a constant speed of 1.21m/s in a horizontal circle of radius 0.44m

a) Find the angle the string make with the vertical

b) the tension in the string

I found the answer to a. What I did was use the formula

Thea=tan-1(Vsquare/gr)

V=1.21m/s

g=9.81m/s square

r=0.44m

So the answer is 18.7 degree

How do I slove for the tension of the string?

**Question 3:**

A monkey swings a ball tied to a string in a circle over her head at constant speed. The ball:

a. has total force acting on it that is zero.

b. has a total force acting on it that it is not zero.

c. has an acceleration that is zero. (not C because constantly have accer because constanly changing direction)

d. has a constant velocity.

**Question 4:**

A box is pushed along a horizontal surface with a horizontal force that is equal in magnitude to the force of kinetic friction between the box and surface. In this case:

a. the box's speed will decrease at a constant rate.

b. the box's speed will increase at a constant rate.

c. the book will not be able to move, because the coefficent of static friction must exceed the coefficient of kinetic friction.

d. the box will move at constant speed.

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