A particle is released from a height of S above the surface of the earth. At a certain height, its kinetic energy is three times its potential energy. The distance from the earth's surface and the speed of the particle at that instant are respectively:
Body A of mass 4m moving with speed u collides with another body B of mass 2m at rest. The collision is head-on and elastic in nature. After the collision, the fraction of energy lost by the colliding body A is:
When an object is shot from the bottom of a long, smooth inclined plane kept at an angle of 60 with horizontal, it can travel a distance along the plane. But when the inclination is decreased to 30 and the same object is shot with the same velocity, it can travel distance. Then : will be:
A force F= 20+10y acts on a particle in the y-direction where F is in Newton and y is in meter. Work done by this force to move the particle from y = 0 to y = 1m is:
1. 20 J
2. 30 J
3. 5 J
4. 25 J
A mass m is attached to a thin wire and whirled in a vertical circle. The wire is most likely to break when:
1. inclined at an angle of from vertical.
2. the mass is at the highest point.
3. the wire is horizontal.
4. the mass is at the lowest point.
A disc of radius 2 m and mass 100 kg rolls on a horizontal floor. Its centre of mass has speed of 20 cm/s. How much work is needed to stop it?
1. 1 J
2. 3 J
3. 30 J
4. 2 J
An object of mass 500 g initially at rest is acted upon by a variable force whose x-component varies with x in the manner shown. The velocities of the object at the points x = 8 m and x = 12 m would have the respective values of nearly:
1. 18 m/s and 24.4 m/s
2. 23 m/s and 24.4 m/s
3. 23 m/s and 20.5 m/s
4. 18 m/s and 20.5 m/s
Water falls from a height of 60m at the rate of 15kg/s to operate a turbine. The losses due to frictional forces are 10% of energy. How much power is generated by the turbine? (g=10 m/)
1. 8.1 kW 2. 10.2 kW
3. 12.3 kW 4. 7.0 kW