Answer:
19.48 m
Explanation:
Gravitational potential energy = mgh
Current weight = 539 N
Weight = mg = 539 N
Mass x Acceleration = 539 N
Mass x 9.81 = 539
Mass = 54.94 kg
Gravitational potential energy = mgh = 10500 J
54.94 x 9.81 x h = 10500
h = 19.48 m
Height of sitting = 19.48 m
Answer:

Explanation:
Momentum is the product of mass and velocity.

The mass of the truck is 2,000 kilograms and the velocity is 35 meters per second.

Substitute the values into the formula and multiply.

The truck's momentum is <u>70,000 kilograms meters per second.</u>
Answer
given,
height of Alpe d'Huez = 1100-m
time = 37.5 min
mass of the rider and his bike = 65 Kg
the metabolic power to ride = 700 W
U = m g y
U = 65 x 9.8 x 1100
U = 700700 J
since efficiency is 25%





b) 

P = 1245.68 W
Answer:
16.33°C
Explanation:
Applying,
Heat lost by copper = heat gained by water
cm(t₁-t₃) = c'm'(t₃-t₂).............. Equation 1
Where c = specific heat capacity of copper, m = mass of copper, c' = specific heat capacity of water, m' = mass of water, t₁ = initial temperature of copper, t₂ = initial temperature of water, t₃ = final equilibrium temperature.
From the question,
Given: m = 50 kg, t₁ = 140°C, m' = 90 L = 90 kg, t₂ = 10°C
Constant: c = 385 J/kg°C, c' = 4200J/kg°C
Substitute these values into equation 1
50(385)(140-t₃) = 90(4200)(t₃-10)
(140-t₃) = 378000(t₃-10)/19250
(140-t₃) = 19.64(t₃-10)
140-t₃ = 19.64t₃-196.6
19.64t₃+t₃ = 196.4+140
20.64t₃ = 336,4
t₃ = 336.4/20.6
t₃ = 16.33°C