Review 83500 J

1. A 90.0 kg man climbs hand over hand up a rope to a height of 9.47 m. How

much potential energy does he have at the top?

2. A 50.0 kg shell was fired from a cannon at earth's surface to a maximum

height of 400. m.

a. What is the potential energy at maximum height?

b. It then fell to a height of 100. m. What was the loss of PE as it fell?

3. A person weighing 645 N climbs up a ladder to a height of 4.55 m.

a. What work does the person do?

b. What is the increase in gravitational potential energy?

c. Where does the energy come from to cause this increase in PE?

pecialized keyboards

speed of light in vacuum is 300,000 km/s

speed of light in other mediums is given by the expression v = c/n, where c is the speed of light in vacuum and n is the refractive index of medium.

for the first medium v = 200,000 km/s

  so, refractive index of medium = 300000/200000 = 1.5

    1.5 refractive index is usually for glass. so first medium is glass.

for the second medium v = 250,00 km/s

so, refractive index of medium = 300000/250000 = 1.2

    1.2 refractive index is usually for water. so second medium is water.

for the third medium v = 0 km/s

so, refractive index of medium = 300000/0 = ∞

    ∞ refractive index is usually for opaque mediums. so third medium is opaque medium.

find the surface area of the sphere to the nearest square unit. use a calculator.

a. 254 in.2

b. 64 in.2

c. 127 in.2

d. 1,018 in.2