Hey!
Formula for calculating work = Force × distance
Work done = Force applied on the object × distance travelled by it.
Hope it helps...!!!
Answer:
Explanation:
Potential Energy= Kinetic Energy
Let 
be the value of Kinetic Energy.
We know that
Make 
the subject of the formula to get speed at the bottom of the hill.
Answer:
Vr = 3.24m/s
The boat is going 3.24m/s relative to the bank of the river.
Explanation:
The relative speed of the boat to the bank Vr is the resultant of speed of boat relative to the water Vb and the speed of boat as a result of the water current or wind Vw
Vr = √(Vb^2 + Vw^2) .....1
Given;
Vb = 2.6m/s
Vw = distance downstream/time = 690m/355s
Vw = 1.94m/s
From equation 1 above; substituting the values
Vr = √(2.6^2 + 1.94^2)
Vr = 3.24m/s
The boat is going 3.24m/s relative to the bank of the river.
Surface tension<span> is a property of the surface of a liquid that allows it to resist an external force. for example, some objects can float on the surface of water, even though they are denser than water, and in the ability of some insectsto run on the water surface. This property is caused by cohesion of similar molecules, and is responsible for many of the behaviors of liquids.</span>
