Answer:
Time, t = 4.08 secs
Explanation:
<u>Given the following data;</u>
Initial velocity, U = 40m/s
To find the time, we would use the first equation of motion;
Where;
<em>Making time, t the subject of formula, we have;</em>
We know that acceleration due to gravity, g is 9.8m/s².
a = g = - 9.8m/s² because the ball is thrown in the opposite direction.
Also, the final velocity is equal to zero (0) because the ball reached its maximum height.
<em>Substituting into the equation, we have;</em>
Time, t = 4.08 secs
<em>Therefore, it will take the ball 4.08 seconds to reach the top. </em>
Explanation:
The given data is as follows.
mass (m) = 170 kg, Distance (s) = 9.6 m
Height (h) = 3.3 m, Force (F) = 1400 N
First, we will calculate the work performed by her as follows.
W = Fs
=
= 13440 J
Hence, minimal work necessary to lift the refrigerator is as follows.
U = mgh
=
= 5497.8 J
Therefore, we can conclude that he performed 5497.8 J of work.
Answer:
Approximately 0.0898 W/m².
Explanation:
The intensity of light measures the power that the light delivers per unit area.
The source in this question delivers a constant power of . If the source here is a point source, that
of power will be spread out evenly over a spherical surface that is centered at the point source. In this case, the radius of the surface will be 9.6 meters.
The surface area of a sphere of radius is equal to
. For the imaginary 9.6-meter sphere here, the surface area will be:
.
That power is spread out evenly over this 9.6-meter sphere. The power delivered per unit area will be:
.