Work by Multiple Forces
Trending Questions
Q. Figure shows three forces applied to a block that moves leftward by 3 m over a smooth floor. The magnitudes of force are F1=5 N, F2=9 N and F3=3 N. The net work done on the block by the three forces will be
![](https://df0b18phdhzpx.cloudfront.net/ckeditor_assets/pictures/890480/original_RM_qstn_5.png)
![](https://df0b18phdhzpx.cloudfront.net/ckeditor_assets/pictures/890480/original_RM_qstn_5.png)
- 1.5 J
- 3.6 J
- 3 J
- 4.5 J
Q. In a simple pendulum, work done by tension is non zero.
- False
- True
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:
![](https://df0b18phdhzpx.cloudfront.net/ckeditor_assets/pictures/942461/original_1.png)
![](https://df0b18phdhzpx.cloudfront.net/ckeditor_assets/pictures/942461/original_1.png)
- 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. A body of mass m kg is lifted by a man to a height of one metre in 30 sec. Another man lifts the same mass to the same height in 60 sec. The work done by them(approximately) are in the ratio
- 1 : 2
- 1 : 1
- 2 : 1
- 4 : 1
Q. Three forces act on block as shown in figure.
![](https://df0b18phdhzpx.cloudfront.net/ckeditor_assets/pictures/815705/original_Extra_2.png)
Find work done by net force, if the block moves 10 m in horizontal direction
Given magnitudes of forces are
[F1=20 N, F2=5√2 N, F3=10 N]
![](https://df0b18phdhzpx.cloudfront.net/ckeditor_assets/pictures/815705/original_Extra_2.png)
Find work done by net force, if the block moves 10 m in horizontal direction
Given magnitudes of forces are
[F1=20 N, F2=5√2 N, F3=10 N]
- 50 J
- 100 J
- 75 J
- Work done is equal to zero as there is no friction.
Q. Three forces are acting on the block as shown in figure.
![](https://df0b18phdhzpx.cloudfront.net/ckeditor_assets/pictures/831261/original_Pictur1.png)
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]
![](https://df0b18phdhzpx.cloudfront.net/ckeditor_assets/pictures/831261/original_Pictur1.png)
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.
Multiple constant forces F1, ......Fi are acting on an object of mass 'm' and produce a displacement S, with an acceleration a. Which of the following statements is true.
Work done on the object is ∑ni=1→Fi.→S
Work done on the object is (∑ni=1→Fi).→S
Work done on the object is m→a.→S
If all the forces are acting in the same direction, then work done will be maximum
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 of −→F2=(3^i+4^j) N, displaces it from (−1, −1, 3) to (5, 5, 5) (displacements being measure in metre). Find the total work done.
- 46 J
- 38 J
- 40 J
- 36 J
Q. In the arrangement shown, the block is released from rest from x=0 (when the spring was in its natural length), on a rough incline surface having μ=0.5x. The maximum elongation in the spring will be,
![](https://df0b18phdhzpx.cloudfront.net/ckeditor_assets/pictures/1498269/original_17.png)
![](https://df0b18phdhzpx.cloudfront.net/ckeditor_assets/pictures/1498269/original_17.png)
- 2 m
- 2.5 m
- 1 m
- 1.5 m
Q. A particle is shifted from point (0, 0, 1 m) to (1 m, 1 m, 2 m), under the simultaneous action of several forces. Two of the forces are −→F1=(2^i+3^j−^k) N and −→F2=(^i−2^j+2^k) N. Find the work done by these two forces
- 7 J
- 5 J
- 10 J
- 12 J
Q. The total work done by three forces on a block is 60 J. If block is displaced by a force from position A(1, 2, 3) to B(7, 6, 5). Find out the third force if the other two forces are −→F1=(7^i+3^j+2^k) N, and −→F2=(−2^i+2^j+^k) N.
Assume that −→F3 is perpendicular to XY plane.
Assume that −→F3 is perpendicular to XY plane.
- −→F3=^k
- −→F3=2^k
- −→F3=3^k
- −→F3=4^k
Q. Three forces act on block as shown in figure.
![](https://df0b18phdhzpx.cloudfront.net/ckeditor_assets/pictures/815705/original_Extra_2.png)
Find work done by net force, if the block moves 10 m in horizontal direction
Given magnitudes of forces are
[F1=20 N, F2=5√2 N, F3=10 N]
![](https://df0b18phdhzpx.cloudfront.net/ckeditor_assets/pictures/815705/original_Extra_2.png)
Find work done by net force, if the block moves 10 m in horizontal direction
Given magnitudes of forces are
[F1=20 N, F2=5√2 N, F3=10 N]
- 50 J
- 100 J
- 75 J
- Work done is equal to zero as there is no friction.