Answer:
Explained below
Explanation:
A) Newton's first law of motion states that an object will remain at rest or continue in its current state of motion except it is acted upon by another force.
Now using this law, when you jump off the ground, the earth will move a tiny bit and accelerate due to the force applied by the jumping.
B) Newton's 2nd law states that the acceleration of a system is directly proportional to the net external force acting on that system, is in the same direction with it and also inversely proportional to the mass.
In this case, when one jumps, an external force is exerted on the earth and we are told it is directly proportional to the acceleration of the system which in this case it's the earth, then it means that there is some motion by the earth even though you didn't see it move.
C) Newton's third law of motion states that to every action, there is an equal and opposite reaction.
In this case the motion of the jumper will lead to an equal and opposite reaction of the earth.
Chemical energy is transformed in your body
Since this is a distance/time graph, the speed at any time is the slope
of the part of the graph that's directly over that time on the x-axis.
At time t1 = 2.0 s
That's in the middle of the first segment of the graph,
that extends from zero to 3 seconds.
Its slope is 7/3 . v1 = 7/3 m/s .
At time t2 = 4.0 s
That's in the middle of the horizontal part of the graph
that runs from 3 to 6 seconds.
Its slope is zero.
v2 = zero .
At time t3 = 13 s.
That's in the middle of the part of the graph that's sloping down,
between 11 and 16 seconds.
Its slope is -3/5 . v3 = -0.6 m/s .
Answer:
a) 29.4 J
b) - 29.4 J
Explanation:
Given:
Mass of the book, m = 2 kg
Height above the floor, h = 1.5 m
Now,
the work done by the person will be = Force applied on the book × displacement of the book
thus,
Work done by the person = mg × h
where, g is the acceleration due to gravity
thus, on substituting the values, we get
Work done by the person = 2 × 9.8 × 1.5 = 29.4 J
now,
for the force applied by the gravitational pull (downwards) the displacement is in opposite direction (upwards) to the force of the gravity.
Thus,
work done by the gravity will be negative
therefore, the work done by the gravity = - mg × h
or
work done by the gravity = - 29.4 J
