A wheel is rotating about an axis through its centre at \(720\) r.p.m. It is acted upon by a constant torque opposing its motion for \(8\) seconds to bring it to rest finally.
The value of torque in N-m is: (given \(I\) = kg )
1. \(48\)
2. \(72\)
3. \(96\)
4. \(120\)
A wheel is rotating 900 rpm about its axis. When power is cut off it comes to rest in 1 min. The angular retardation in rad/s2 is
1.
2.
3.
4.
An automobile engine develops 100 kW when rotating at a speed of 1800 rev/min. What torque does it deliver ?
1. 350 N-m
2. 440 N-m
3. 531 N-m
4. 628 N-m
In an orbital motion, the angular momentum vector is
1. Along the radius vector
2. Parallel to the linear momentum
3. In the orbital plane
4. Perpendicular to the orbital plane
A wheel is at rest. Its angular velocity increases uniformly and becomes 80 rad/s after 5 s. The total angular displacement is
1. 800 rad
2. 400 rad
3. 200 rad
4. 100 rad
A force\(- F \hat k\) acts on O, the origin of the coordinate system. The torque at the point (1, -1) will be:
1.
2.
3.
4.
A wheel whose moment of inertia is 12 has an initial angular velocity of 40 rad/sec. A constant torque of 20 Nm acts on the wheel. The time in which the wheel is accelerated to 100 rad/sec is
1. 72 seconds
2. 16 seconds
3. 8 seconds
4. 36 seconds
A constant torque acting on a uniform circular wheel changes its angular momentum from to in 4s. The magnitude of this torque is
1.
2.
3.
4.
A solid cylinder rolls down an inclined plane that has friction sufficient to prevent sliding. The ratio of rotational energy to total kinetic energy is
1.
2.
3.
4.
A swimmer while jumping into water from a height easily forms a loop in the air, if
1. He pulls his arms and legs in
2. He spreads his arms and legs
3. He keeps himself straight
4. None of the above