Answer:652.05 J
Explanation:
Given
Weight of lifter 
vertical distance move 
Work done in lifting the weight is equal change in Potential Energy of weight
Change in Potential Energy 

therefore work done is equal to
Answer:

Explanation:
If the collision is elastic and exactly head-on, then we can use the law of momentum conservation for the motion of the 2 balls
Before the collision

After the collision

So using the law of momentum conservation


We can solve for the speed of ball 1 post collision in terms of others:

Their kinetic energy is also conserved before and after collision


From here we can plug in 






Answer:
a I think hope this helps
Answer:
V4=9.197v
Explanation:
Given:
V1= 18v ,V2= 12v ,r1=r5=58ohms ,r2=r6=124ohms , r3=47ohms ,r4= 125ohms
V4= I4R4 = V2/(R4 + R5)×R4
V4= 12×125 /(125 + 58)
V4=1500/183 =9.197v