Assignments | Chapter 5 | Work & Energy | Physics 11th | National Book Foundation | Federal Board

Click on the link below for latest videos. https://whatsapp.com/channel/0029VaGr... Q. Encircle the correct option. If the unit of force and displacement travelled each be increased five times, then the unit of work will be increased by (a) 25 times (b) 10 times (c) 5 times (d) 0 times The force that acts on a body but does no work is (a) gravitational force (b) frictional force (c) elastic force (d) centripetal force The odd force from the following is (a) gravitational force (b) elastic force (c) frictional force (d) electric force The work done by a body while covering a vertical height of 10m is 500J. By how much amount does the energy of the body change? (a) 500J (b) -500J (c) 50J (d) -50J Is it possible that a force is acting on a body and the body is in motion due to this force but the work done after certain time is zero? Some non-conservative forces are acting on a body. Can they change the total mechanical energy of the body? Kinetic energy and work are related. Can kinetic energy ever be negative? Can work ever be negative? Differentiate between conservative and non-conservative forces. What is the work done by the moon as it revolves around the Earth? A car carrying truck unloads a 1500kg car using a plank as shown in figure. If the plank makes an angle of 30° with the ground and its upper end is at 2m height, what will be the work done by gravitational force? Also, draw the force-displacement graph for. A car, having total mass of 1500kg (including the driver), is travelling at a speed of 40kph through a straight path. How much will be required to stop the said car if its brakes fail and engine turns off? A ball of mass 100g is released from a height of 30m. If the ball encounters an air resistance of 0.4N, find the kinetic energy of the ball just before striking the ground.