Question 138: Work, Energy and Power & Circular Motion

Question

A block of mass m is kept on a platform which starts from rest with constant acceleration g/2 upward, as shown in figure. Work done by normal reaction on block in time is -

Accepted Answer

N $$-$$ mg = $${{mg} \over 2}$$ $$ \Rightarrow $$  N = $${{3mg} \over 2}$$
The distance travelled by the system in time t is
S = ut + $${1 \over 2}a{t^2} = 0 + {1 \over 2}\left( {{g \over 2}} \right){t^2} = {1 \over 2}{g \over 2}{t^2}$$
Now, work done
W = N.S = $$\left( {{3 \over 2}mg} \right)\left( {{1 \over 2}{g \over 2}{t^2}} \right)$$
$$ \Rightarrow $$  W = $${{3m{g^2}{t^2}} \over 8}$$

Answer

$${{m{g^2}{t^2}} \over 8}$$

Answer

$${{3m{g^2}{t^2}} \over 8}$$

Answer

$$-$$ $${{m{g^2}{t^2}} \over 8}$$

Answer

0

Work, Energy and Power & Circular Motion

A block of mass m is kept on a platform which starts from rest with constant acceleration g/2 upward, as shown in figure. Work done by normal reaction on block in time is -

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