Question

Problem 1: A car of mass 1000 kg moves at a constant speed of 20 m/s along a horizontal road where a frictional force is 200N. Calculate the power developed by the engine. If the car now moves up an incline at the same constant speed, calculate the new power developed by the engine. Assume that the frictional force is still 200 N and that sin(theta)=1/20 where theta is the angle of the incline to the horizontal. Problem 2: An airplane pilot wishes to fly due north. A wind 30 km/hr is blowing towards the west. If the flying speed of the plane is 360km/hr. In what direction should the pilot set his course? What is the speed of the plane over the ground? Problem 3: A bullet of mass 10 g is fired vertically with a velocity of 100 m/s into a block of wood of mass 190 g suspended by a long string above the gun. If the bullet comes to rest in the block, through what height does the block move? Problem 4: A ball of mass 0.2kg falls from a height of 45 m. On striking the ground it rebounds in 0.1s with two- thirds of the velocity with which it struck the ground. Calculate (i) the momentum change on hitting the ground (ii) the force on the ball due to impact. Problem 5: A ball of mass 0.1 kg moving with a velocity of 6m/s collides directly with a ball of mass 0.2 kg at rest. (i) Calculate the common velocity if both balls move together. (ii) If 'A' had rebounded with a velocity of 2m/s, what would be the new velocity of B? Problem 6: An object of mass 8 kg is whirled round in a vertical circle of radius 2m with a constant speed of 6m/s. Calculate the maximum and minimum tensions in the string.

Answer 1

Poublem Sol V-20n/s Va 20mls ngue f200N E2.866 Sine= 20 200N 6 Sin- Ais we knew the foomla fa fowen dewelspe . ( 2.866 E 200x 20 W P fow or develsped the eine Now Car Moves uy an incline at Same conytant speed Sin =msinf -0 00 X9.81 X +200 20 F=90.5N New Pouen develped byhe e x V 690.5x 20 W = 1381d W 13.81 k W