Answer:
The work done on the box is 100 Nm
The power is 20 Nm/s
Explanation:
There is a force 25 newtons moves a box a distance of 4 meters in
5 seconds
The work done on the box is the product of the force and the distance
that the box moves ⇒ <em>work = force × distance</em>
The force = 25 newtons
the distance = 4 meters
Work = 25 × 4 = 100 NM
<em>The work done on the box is 100 Nm</em>
<em></em>
The force moves the box 4 meters in 5 seconds
The power is the rate of work
<em>The power = work ÷ time</em>
The work = 100 Nm
The time = 5 seconds
The power = 100 ÷ 5 = 20 Nm/s
<em>The power is 20 Nm/s</em>
Answer:
a). 87.5 mA or
A
b). 1.78 
Explanation:

n the number of free electrons is 28 in text reference and if they don't give q is take as the charge of electron.
a).
A
b).


Answer:
Calculating Coefficient of friction is 0.229.
Force is 4.5 N that keep the block moving at a constant speed.
Explanation:
We know that speed expression is as
.
Where,
is initial speed, V is final speed, ∆s displacement and a acceleration.
Given that,
=3 m/s, V = 0 m/s, and ∆s = 2 m
Substitute the values in the above formula,

0 = 9 - 4a
4a = 9

is the acceleration.
Calculating Coefficient of friction:


Compare the above equation

Cancel "m" common term in both L.H.S and R.H.S





Hence coefficient of friction is 0.229.
calculating force:


F = 4.5 N
Therefore, the force would be <u>4.5 N</u> to keep the block moving at a constant speed across the floor.
Answer:
170 N
Explanation:
Given in the question that, work a bulldozer can do = 4500 J
<h3>
Step 1</h3>
We will use trigonometry identity to find the distance bulldozer will travel up the hill
sin(35) = opp/hypo
sin(35) = 15/hypo
hypo = 15/sin(35)
hypo = 26.15m
<h3>Step 2</h3>
Formula to use
work done = force × distance
Plug values in the above formula
4500 = force x 26.15
force = 4500/26.15
force = 172.08
force ≈ 170 N
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