1
JEE Main 2021 (Online) 22th July Evening Shift
+4
-1
A porter lifts a heavy suitcase of mass 80 kg and at the destination lowers it down by a distance of 80 cm with a constant velocity. Calculate the work done by the porter in lowering the suitcase.

(take g = 9.8 ms$$-$$2)
A
+627.2 J
B
$$-$$62720.0 J
C
$$-$$627.2 J
D
784.0 J
2
JEE Main 2021 (Online) 20th July Evening Shift
+4
-1
A body at rest is moved along a horizontal straight line by a machine delivering a constant power. The distance moved by the body in time 't' is proportional to :
A
$${t^{{3 \over 2}}}$$
B
$${t^{{1 \over 2}}}$$
C
$${t^{{1 \over 4}}}$$
D
$${t^{{3 \over 4}}}$$
3
JEE Main 2021 (Online) 18th March Morning Shift
+4
-1
A constant power delivering machine has towed a box, which was initially at rest, along a horizontal straight line. The distance moved by the box in time 't' is proportional to :-
A
t2/3
B
t3/2
C
t
D
t1/2
4
JEE Main 2021 (Online) 17th March Morning Shift
+4
-1
A boy is rolling a 0.5 kg ball on the frictionless floor with the speed of 20 ms-1. The ball gets deflected by an obstacle on the way. After deflection it moves with 5% of its initial kinetic energy. What is the speed of the ball now?
A
14.41 ms$$-$$1
B
19.0 ms$$-$$1
C
4.47 ms$$-$$1
D
1.00 ms$$-$$1
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