Question 1

The Earth is about 81 times as massive as the Moon. Suppose the earth and Moon are 10 distance units apart. If you were an astronaut between the Earth and Moon at how many distance units from the Earth will the gravitational attraction on you from the two bodies be equal and opposite?

Accepted Answer

A)  81 units 
B)  9 units 
C)  19 units 
D)  1 unit

Question 2

Why does a skateboarder lean while negotiating a curve?

Accepted Answer

A)  To keep from tipping over by making sure the net force on them is directed towards the skateboard. 
B)  It saves energy 
C)  It lowers air resistance 
D)  To lessen gravitational torque on their center of mass.

Question 3

Compared to planets close to the sun, and based upon Kepler's third law of planetary motion, the length of the year of planets farther out from the sun are

Accepted Answer

A)  the same 
B)  less 
C)  larger 
D)  more information is necessary.

Question 4

You are riding a multi-speed bicycle up a steep hill that's 100 m high and want to do as little work as possible on your way up the hill.

Accepted Answer

A)  You should choose the largest crank sprocket (attached to the pedals) and the smallest freewheel sprocket (attached to the rear wheel). 
B)  You should choose the smallest crank sprocket (attached to the pedals) and the largest freewheel sprocket (attached to the rear wheel). 
C)  You should choose the largest crank sprocket (attached to the pedals) and the largest freewheel sprocket (attached to the rear wheel). 
D)  Your choice of gears doesn't matter because you'll do the same amount of work climbing the hill no matter which gear you choose.

Question 5

In studying many martial arts, it is necessary to practice efficient and safe postures. One important concept related to how one should stand is that the feet should be reasonably far apart, because

Accepted Answer

A)  the base of support is wider, thus stabilizing the person. 
B)  the weight on each foot will be less than when standing normally. 
C)  the weight on each foot will be more than when standing normally. 
D)  the friction force increases, giving the person more traction.

Exam 4: Mechanical Objects, Part 2

The Earth is about 81 times as massive as the Moon. Suppose the earth and Moon are 10 distance units apart. If you were an astronaut between the Earth and Moon at how many distance units from the Earth will the gravitational attraction on you from the two bodies be equal and opposite?

Why does a skateboarder lean while negotiating a curve?

Compared to planets close to the sun, and based upon Kepler's third law of planetary motion, the length of the year of planets farther out from the sun are

You are riding a multi-speed bicycle up a steep hill that's 100 m high and want to do as little work as possible on your way up the hill.

In studying many martial arts, it is necessary to practice efficient and safe postures. One important concept related to how one should stand is that the feet should be reasonably far apart, because