Question

.
26. A vacant truck of mass 1000 kg has speed of 72 km/h. Find out speed of truck full
of 1000 kg stones.​

Answer 1

Answer:

Solution:

Weight of truck = Force = 1000 kgf

Mass = 1000 kg

Initial velocity = 36 km\ h^{-1}km h

−1

= \frac{36\times1000}{60\times60}

60×60

36×1000

= 10 m\ s^{-1}m s

−1

New velocity = 72 km\ h^{-1}km h

−1

= \frac{72\times1000}{60\times60}

60×60

72×1000

= 20 m\ s^{-1}m s

−1

Work done = Increase in energy

= \frac{1}{2}mv^2-\frac{1}{2}mu^2

2

1

mv

2

−

2

1

mu

2

= \frac{1}{2}m\left(v+u\right)\left(v-u\right)

2

1

m(v+u)(v−u)

= \frac{1}{2}\times1000\times30\times10

2

1

×1000×30×10

= 150000 J

= 1.5\times10^5\1.5×10

5

J