Answer: 
Explanation:
Given
Diameter of the rod 
length of rod is 
Resistivity of silicon is 
cross-section of the rod 

Resistance of rod is R


Current is given by

Answer:
d.Energy as heat transferred into an object is determined by the amount of work done on the object.
Explanation:
A crazy sport thats kinda dangerous
Answer:
2.7
Explanation:
The following data were obtained from the question:
Mass (m) of box = 100 Kg
Length (L) of ramp = 4 m
Height (H) of ramp = 1.5 m
Mechanical advantage (MA) of ramp =?
Mechanical advantage of a ramp is simply defined as the ratio of the length of the ramp to the height of the ramp. Mathematically, it is given by:
Mechanical Advantage = Lenght / height
MA= L/H
With the above formula, we can obtain the mechanical advantage of the ramp as follow:
Length (L) of ramp = 4 m
Height (H) of ramp = 1.5 m
Mechanical advantage (MA) of ramp =?
MA = 4/1.5
MA = 2.7
Therefore, the mechanical advantage of the ramp is 2.7
The power expended is 500 W
Explanation:
First of all, we start by calculating the work done by the man in order to ascend: this is equal to the gravitational potential energy gained by the man, which is

where
m = 50 kg is the mass of the man
is the acceleration of gravity
is the change in height
Substituting,

Now we can calculate the power expended, which is given by

where
W = 2500 J is the work done
t = 5 s is the time elapsed
Substituting, we find

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