Answer:
Time = t = 6.62 s
Explanation:
Given data:
Height = h = 215 m
Initial velocity =
= 0 m/s
gravitational acceleration = g = 9.8 m/s²
Time = t = ?
According to second equation of motion

As initial velocity is zero, So the first term of right hand side of above equation equal to zero.

t² = 
t =
t = 
t = 6.62 s
Answer: 150 m
Explanation:
velocity = 22 m/s
t = 6.8 s
velocity = 
distance = velocity × time
= 22 × 6.8
= 149.6 m
≈ 150 m
option C
Answer:
C) No work is required to move the negative charge from point A to point B.
Explanation:
An equipotential surface is defined as a surface connecting all the points at the same potential.
Therefore, when a charge moves along an equipotential surface, it moves between points at same potential.
The work done when moving a charge is given by

where
q is the charge
is the potential difference between the initial and final point of motion of the charge
However, the charge in this problem moves along an equipotential surface: this means that the potential does not change, so

And so, the work done is also zero.
Answer:
39.240 W
Explanation:
Let's start by calculating the work done by the engine. We can assume that it is the same work done by the weight of the object to bring it from 40m to the surface: as much energy it takes to bring it up, the same ammount it takes to bring it down. Said work is 
At this point we can simply apply the definition of power, that is
, to get the power of the engine is 
Answer:c
Explanation: the speed of object a changes but b travels at constant speed