-- more mass involved
-- less distance between the two objects
Answer:
456.4 N
Explanation:
From conservation of energy, the potential energy is converted to kinetic energy hence
mgh=½mv²
Making v the subject then

Where g is acceleration due to gravity and h is height whike v is final velocity. Substituting 4.9m for h and 9.81 m/s² for g then

Change in momentum equals to the impulse.
Impulse, I= Ft
Change in momentum, ∆p= m(v-u)
Ft=m(v-u) making F the subject of formula then

Where F is force in Newton, t is time in seconds, m is mass of diver, v and u are the final and initial velocities respectively.
Substituting 68 kg for m, 9.8 m/s for v, 0 m/s for u since it is initially at rest and 1.46 s for t

Work done to lift the rock is 6174 Joule.
To find the answer, we need to know about the work done.
<h3>What's the work done?</h3>
Mathematically, work done = force × distance
<h3>What's the gravitational force acts on the stone here?</h3>
The gravitational force on the stone = mg
= 210× 9.8= 2058N
<h3>What's the work done to lift the stone?</h3>
Work done= 2058× 3
= 6174 Joule
Thus, we can conclude that the work done to lift the stone is 6174 Joule.
Learn more about the work done here:
brainly.com/question/25573309
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Answer:
b) in a direction that makes its potential energy decrease.
Explanation:
- As the electric field has the direction that would take a positive test charge under its sole influence, the positive test charge, will have an increase in its kinetic energy.
- Due to the conservation of energy, in absence of non-conservative forces, this increment must be equal and opposite to the change in electric potential energy, which will be always negative, independent of the sign of the charge.
No, they won't, mass coincides with density and objects have different densities a one pound lead ball would be smaller than a one pound copper one.