A construction crane is on top of a skyscraper which has height 45m. The crane itself is 10m in height. What is the gravitational potential energy in joules of a 60kg worker who is standing on top of the crane? (Use g=9.81 in your calculations)

32340J

Explanation:

Given parameters

Height of skyscraper  = 45m

Height of crane  = 10m

Mass of worker = 60kg

g = 9.81m

Unknown:

Gravitational potential energy  = ?

Solution:

The gravitational potential energy of a body is the energy due to the position of the body.

It is expressed as:

     G.P.E  = mgh

m is the mass

g is the acceleration due to gravity

h is the height = 45 + 10  = 55m

G.P.E  = 60 x 9.8 x 55  = 32340J

when a device is used in a circuit in which the voltage is 81 v, the current flowing through the device is 3 a. what is the resistance of the device?

a. 27 ω

b. 40.5 a

c. 243 ω

d. 243 a

the correct answer is a. 27