Questions in Laws of Motion

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A man is standing on a weighing machine placed in a lift. When stationary his weight is recorded as 40 kg. If the lift is accelerated upwards with an acceleration of $2\,m/{s^2}$, then the weight recorded in the machine will be $(g = 10\,m/{s^2})$
A body of mass 4 kg weighs 4.8 kg when suspended in a moving lift. The acceleration of the lift is
An elevator weighing 6000 kg is pulled upward by a cable with an acceleration of $5\,m{s^{ - 2}}$. Taking g to be $10\,m{s^{ - 2}}$, then the tension in the cable is
A ball of mass 0.2 kg moves with a velocity of 20 m/sec and it stops in 0.1 sec; then the force on the ball is
A vehicle of 100 kg is moving with a velocity of 5 m/sec. To stop it in $\frac{1}{{10}}\sec $, the required force in opposite direction is
A boy having a mass equal to 40 kilograms is standing in an elevator. The force felt by the feet of the boy will be greatest when the elevator $(g = 9.8\,metres/{\sec ^2})$
A rocket has an initial mass of $20 \times {10^3}\,kg$. If it is to blast off with an initial acceleration of $4\,m{s^{ - 2}}$, the initial thrust needed is $(g\tilde = 10\,m{s^{ - 2}})$
The ratio of the weight of a man in a stationary lift and when it is moving downward with uniform acceleration ‘a’ is 3 : 2. The value of ‘a’ is (g-Acceleration due to gravity of the earth)
The mass of a lift is 500 kg. When it ascends with an acceleration of $2\,m/{s^2}$, the tension in the cable will be $[g = 10\,m/{s^2}]$
If force on a rocket having exhaust velocity of 300 m/sec is 210 N, then rate of combustion of the fuel is

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