A solid disc of mass M is held horizontally i | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(A) The weight of the disc is balanced by the average force exerted by the stones on the disc.When a stone strikes the disc and stops (or rebounds),it

Vedclass · Accepted Answer

$1.2$

Vedclass · Answer

(A) The weight of the disc is balanced by the average force exerted by the stones on the disc.When a stone strikes the disc and stops (or rebounds),it exerts an impulsive force.Assuming the stones strike and come to rest relative to the disc (or transfer their full momentum),the force $F$ exerted by $n$ stones per second is given by the rate of change of momentum:$F = n \cdot \Delta p = n \cdot m \cdot v$Given $n = 40\,s^{-1}$,$m = 0.05\,kg$,and $v = 6\,m/s$:$F = 40 	imes 0.05 	imes 6 = 12\,N$For the disc to be held in equilibrium,the upward force must equal the weight of the disc:$F = Mg$$12 = M 	imes 10$$M = \frac{12}{10} = 1.2\,kg$

$A$ solid disc of mass $M$ is held horizontally in the air by throwing $40$ stones per second vertically upwards to strike the disc,each with a velocity of $6\,m/s$. If the mass of each stone is $0.05\,kg$,what is the mass of the disc in $kg$? (Take $g = 10\,m/s^2$)

Similar Questions

$A$ rocket motor consumes $100 \ kg$ of fuel per second,exhausting it with a speed of $5 \ km/s$. The speed of the rocket when its mass is reduced to $\frac{1}{20}$ of its initial mass is (Assume initial speed to be zero and ignore gravitational and viscous forces.)

$A$ rocket which has a mass of $3.5 \times 10^4 \,kg$ is blasted upwards with an initial acceleration of $10 \,m/s^2$. The initial thrust of the blast is-

$A$ balloon with mass $m$ is descending vertically with an acceleration $a$ (where $a < g$). The mass to be removed from the balloon so that it starts moving vertically up with an acceleration $a$ is:

$A$ gun of mass $10 \, kg$ fires $4$ bullets per second. The mass of each bullet is $20 \, g$ and the velocity of the bullet when it leaves the gun is $300 \, m/s$. The force required to hold the gun while firing is (in $N$)

$A$ cart is moving with a velocity of $20 \, m/s$. Sand is being dropped into the cart at the rate of $50 \, kg/min$. The force required to move the cart with constant velocity will be ............ $N$.

Vedclass Test Series

Exam Paper Generator

Online Exam Module