Answer:
2.2N
Explanation:
Given parameters:
Work done = 379.5J
Height = 173m
Unknown:
Amount of force exerted on the sled = ?
Solution:
The amount of force she exerted on the sled is the same as her weight.
Work done is the force applied to move a body through a distance.
Work done = mgh
m is the mass
g is the acceleration due to gravity
h is the height
mg = weight;
Work done = weight x h
379.5 = weight x 173
weight =
= 2.2N
Answer:
(a) 
(b) 
Explanation:
(a) The surface current density of a conductor is the current flowing per unit length of the conductor.

Considering a wire, the current is uniformly distributed over the circumferenece of the wire.

The radius of the wire = a

The surface current density 
(b) The current density is inversely proportional
......(1)
k is the constant of proportionality

........(2)
substituting (1) into (2)





substitute 

Answer:
The work done by gravity during the roll is 490.6 J
Explanation:
The work (W) is:

<em>Where</em>:
F: is the force
d: is the displacement = 20 m
The force is equal to the weight (W) in the x component:

<em>Where:</em>
m: is the mass of the bowling ball = 5 kg
g: is the gravity = 9.81 m/s²
θ: is the degree angle to the horizontal = 30°
Now, we can find the work:
Therefore, the work done by gravity during the roll is 490.6 J.
I hope it helps you!
I agree with the other comment
Answer:
The maximum speed will be 26.475 m/sec
Explanation:
We have given mass of the toy m = 0.50 kg
radius of the light string r = 1 m
Tension on the string T = 350 N
We have to find the maximum speed without breaking the string
For without breaking the string tension must be equal to the centripetal force
So 
So 

v = 26.475 m /sec
So the maximum speed will be 26.475 m/sec