Answer:
The amount of power will be increased.
Explanation:
If the work remains constant but the time is reduced the power increases. Since power is defined as the relationship between work overtime. By means of the following equation, we can see this relationship.
where:
P = power [Watts]
W = work [J] (units of joules)
t = time [s]
Let's assume with an example the above written.
If we have an electric motor that exerts a work of 950 [J], and the time used is 5 [s], the power is:
Now if we want to accelerate the work done and use 2 seconds for the time, we will have:
Explanation:
It is given that,
Total mass is 70 kg
The truck exerts a constant force of 20 N.
Then the net force is given by :
F = ma
a is acceleration of rider
Initial velocity of rider is 0. So, using equation of kinematics to find the final velocity as :
Since, 1 m/s = 2.23 mph
4.28 m/s = 9.57 mph
So, the speed of the rider is 4.28 m/s or 9.57 mph.
Answer:
60 boxes
Explanation:
The work done by lifting a single box is equal to the force applied (the weight of the box) times the displacement of the box:
Power is related to the work done by the equation:
where W is the work done and t is the time. In this problem, we are told that the power used is P=60.0 W, while the time taken is t = 1 min = 60 s, so the total work done must be
Therefore, the number of boxes that she has to lift in order to use this power is the total work divided by the work done in lifting each box:
Given,
length of object,
We know, for flat refracting surface,
Image distance = object distance
So,
magnification is =
length of the image,
Here, negative sign means inverted image.
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