Question

a pole vaulter at the top of his vault is 6.15 m in the air . if he has a gravitational potential energy of 4o42 j , what is his mass?

Answer 1

82.0 kg I am going to assume that there is a typo for the number of joules of energy. Doing a google search for this exact question showed this question multiple times with a value of 4942 joules which makes sense given how close the "o" key is to the "9" key. Because of this, I will assume that the correct value for the number of joules is 4942. With that in mind, here's the solution. The gravitational potential energy is expressed as the mass multiplied by the height, multiplied by the local gravitational acceleration. So: E = MHA Solving for M, the substituting the known values and calculating gives: E = MHA E/(HA) = M 4942/(6.15*9.8) = M 4942/60.27 = M 81.99767712 = M Rounding to 3 significant figures gives 82.0 kg

Answer 2

Gravitational potential energy is given by 

 U=mgh

 where 

 m is the mass of the object 

 h is the height of the object above the ground (Earth's surface)

 g is the gravitational acceleration constant, 9.8ms2.

 For h=6.15m and U=4042J, we can rearrange to solve for m:

 m=U/gh

 m=(4042J)/((9.8m/s^2)*(6.15m))

 m=67.06 Kg