Answer:
1) The potential energy, P.E = 4527.6 J
2) The mass, m = 1.28 kg
3) The height of the bell, h = 4.31 m
4) The kinetic energy, K.E = 385 J
5) The velocity of the car, V = 22.53 m/s
6) The mass of the car, m = 17.59 kg
Explanation:
1) The height of the hill, h = 21 m
The carriage with a baby has mass of, m = 22 kg
The potential energy,
P.E = mgh
= 22 x 9.8 x 21
= 4527.6 J
2) The height of the platform, h = 20 m
The P.E of the cinder block, P.E = 250 J
The mass,
m = P.E / gh
= 250 / (9.8 x 20)
= 1.28 kg
3) The mass of the bell, m = 18 kg
The P.E of the bell, P.E = 760 J
The height of the bell,
h = P.E/mg
= 760 / 18 x 9.8
= 4.31 m
4) The mass of the runner, m = 55 kg
The velocity of the runner, v = 14 m/s
The kinetic energy,
K.E = ½ mv²
= ½ x 55 x 14
= 385 J
5)The kinetic energy of the car, K.E = 69,759 J
The mass of the car, m = 275 kg
The velocity of the car,
V = √(2K.E/m)
V = √( 2 x 69759 / 275)
= 22.53 m/s
6) The velocity of the car, v = 38 m/s
The kinetic energy of the car, K.E = 12700 J
The mass of the car,
m = 2 K.E/ v²
= 2 x 12700 / 38²
m = 17.59 kg
