The gravitational potential difference between a point at the surface of a certain planet and a point 10 m above the surface is 4.0 J kg -1. Assuming the gravitational field is uniform, the work done in joule, in moving a mass of 2.0 kg from the surface to a point 5.0 m above the surface is

Question

The gravitational potential difference between a point at the surface of a certain planet and a point 10 m above the surface is 4.0 J kg -1. Assuming the gravitational field is uniform, the work done in joule, in moving a mass of 2.0 kg from the surface to a point 5.0 m above the surface is (A) 0.16 (B) 1.0 (C) 4.0 (D) 2.0

Tardigrade Admin · Accepted Answer

Δ V=(Δ U/m)=(m g Δ h/m)=g Δ h g(10 m )=4 J kg -1, g=((4/10)) J kg -1 ⋅ m -1 W ex =Δ U prime=m prime g Δ h prime=(2 kg )((4/10) J kg -1 m -1)(5 m ) =4 J

Q. The gravitational potential difference between a point at the surface of a certain planet and a point 10m above the surface is 4.0Jkg−1. Assuming the gravitational field is uniform, the work done in joule, in moving a mass of 2.0kg from the surface to a point 5.0m above the surface is

0.16

1.0

4.0

2.0

ΔV=mΔU​=mmgΔh​=gΔh g(10m)=4Jkg−1,g=(104​)Jkg−1⋅m−1 Wex​=ΔU′=m′gΔh′=(2kg)(104​Jkg−1m−1)(5m) =4J

$Δ V = \frac{Δ U}{m} = \frac{m g Δ h}{m} = g Δ h$
$g (10 m) = 4 J k g^{- 1}, g = (\frac{4}{10}) J k g^{- 1} \cdot m^{- 1}$
$W_{e x} = Δ U^{'} = m^{'} g Δ h^{'} = (2 k g) (\frac{4}{10} J k g^{- 1} m^{- 1}) (5 m)$
$= 4 J$