Work by Multiple Forces
Trending Questions
Q.
A man climbs a slope and another walks the same distance on level road. Which of the two expends more energy and why?
Q. A body of mass 2 kg initially at rest moves under the action of an applied horizontal force of 7 N on a table with coefficient of kinetic friction = 0.1. Compute the (a) work done by the applied force in 10 s, (b) work done by friction in 10 s, (c) work done by the net force on the body in 10 s, (d) change in kinetic energy of the body in 10 s, and interpret your results.
Q. A 1 kg block situated on a rough incline is connected to a spring of spring constant 100 N m¯¹ as shown in Fig. 6.17. The block is released from rest with the spring in the unstretched position. The block moves 10 cm down the incline before coming to rest. Find the coefficient of friction between the block and the incline. Assume that the spring has a negligible mass and the pulley is frictionless.
Q. Three forces are acting on the block as shown in figure.
Find work done by net force if block moves 10 m in horizontal direction. Given that [F1=20 N, F2=5√2 N, F3=10 N]
Find work done by net force if block moves 10 m in horizontal direction. Given that [F1=20 N, F2=5√2 N, F3=10 N]
- 50 J
- 100 J
- 75 J
- No work done as friction is absent
Q. A uniform chain of mass m and length l overhangs a table with its two third part on the table. Find the work to be done by a person to put the hanging part back on the table.
Q. a woman lifts a barbell 2m in 5sec. if she lifts it by the same distance in 10sec, the work done by her is
Q. A spring is fixed at the bottom end of an incline of inclination 37∘. A small block of mass 2 kg starts slipping down the incline from a point 4.8 m away (along the inclined plane) from the spring. The block compresses the spring by 20 cm, stops momentarily and then rebounds through a distance of 1 m up the incline. Then:
- Friction co-efficient between the plane and block is 0.7
- Friction co-efficient between the plane and block is 0.5
- Spring constant is 1000 N/m
- Spring constant is 800 N/m
Q. It takes 20 s for a person A to climb up the stairs, while another person B does the same in 45 s and both having same mass. Find
a) Ratio of works done by A and B
b) Ratio of powers expended by A and B
Q. A constant force −→F1=(2^i−4^j) N displaces a particle from (1, −1, 2) to (−1, −1, 3) and then another force −→F2=(3^i+4^j) N displaces it from (−1, −1, 3) to (5, 5, 5) (displacement being measured in metres). Find the total work done.
- 46 J
- 38 J
- 40 J
- 30 J
Q.
a rod of mass m & length l is lying on a horizontal table work done in making it stand on one end will be?
Q. Three constant forces are applied on a body that are given as −→F1=3^i N, −→F2=4^j N, −→F3=6^k N.
If these forces displace the body by 5 m in negative y-axis direction from the origin, then total work done by the forces is
If these forces displace the body by 5 m in negative y-axis direction from the origin, then total work done by the forces is
- 20 N
- 65 N
- −5 N
- −20 N
