Question

If the time to decelerate all the four objects to zero velocity is the same, then in which of the following situation the highest force is applied? a. Truck of mass 650 kg at 1.5 m/s b. Bullet of mass 0.2 kg at 1000 m/s C. Bus of mass 500 kg at 2 m/s d. Boy of mass 60 kg at 10 m/s​

Answer 1

Explanation:

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

Answer 2

Answer:

truck of mass 650 kg at 1.5 mili seconds

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