Answer:
U = 120 lb*ft = 162.698 J
v = 13.105 ft/s
Explanation:
Given
W = 45 lb
L = 32 in
U = ?
v = ?
We apply the equation
U = W*h
where h = L = 32 in*(1 ft/12 in) = 2.66 ft
⇒ U = 45 lb * 2.66 ft = 120 lb*ft
then, we apply
U_in = K_in
⇒ W*h = m*g*h = 0.5*m*v²
⇒ v = √(2*g*h)
⇒ v = √(2*32.2 ft/s²*2.66 ft) = 13.105 ft/s
Answer:
4 m/s.
Explanation:
Given:
W = 45 lb
Converting lb to kg,
45 lb = 20.41 kg
L = 32 in
Converting in to m,
32 in = 81.3 cm
= 0.813 meters
A.
PE = mgh
= 20.41 × 9.81 × 0.813
= 162.78 J
B.
Change in PE = Change in KE
m*g*h = 0.5*m*v²
v = √(2*g*h)
9.8 × 0.813 = 0.5 × v²
v = √(2 × 9.8 × 0.813)
= 4 m/s
