Question

2. A truck has a mass of 3,000 kg and is going 3 m/s. What is the kinetic energy of the truck? Solve using KE = (1/2) mv2 (page 116)

3. A book has a mass of 6 kg and is 15 m above the ground; what is its potential energy? Solve using GPE = mgh (g = 9.81 m/s^2 ; page 118)

4. A power mower does 120,000 J of work in 1200 s. What power does it develop? Solve using P = E/t (page 126)

Answer 1

Answer:

2. Given,

Mass (m) = 3000 kg

Velocity (v) = 3 m/s

K.E = 1/2mv²

= 1/2*3000*3*3 J

= 13500 J

3. Given,

Mass (m) = 6kg

Height (h) = 15m

Acceleration due to gravity (g) = 9.81 m/s²

P.E (u) = mgh

= 6*15*9.81 J

= 882.9 J

4. Given,

Work Done (W) = 120000 J

Time (t) = 1200 s

Power = W/t

= 120000/1200 W

= 100 W or, 0.1 kW

I hope this helps.