Answer:
<h2>Solving elastic collisions problem the hard way</h2><h3 />
Explanation:
perfect drawing
L = illuminance
A = surface
i = intensity
L = i / A ==: i = L * A
i = 6 lux * 4 m^2 = 24 lumen
<h3>It takes 60 seconds to do the work</h3>
<em><u>Solution:</u></em>
Given that,
Force = 100 newtons
Distance = 15 meters
Power = 25 watts
To find: time it takes to do the work
<em><u>Find the work done:</u></em>

<em><u>Find the time taken</u></em>

Thus it takes 60 seconds to do the work
Answer:

Explanation:
It is given that,
Speed of the projectile is 0.5 v. Let h is the height above the ground. Using the first equation of motion to find it.


Initial speed of the projectile is v and final speed is 0.5 v.


g is the acceleration due to gravity
Let h is the height above the ground. Using the second equation of motion as :



So, the height of the projectile above the ground is
. Hence, this is the required solution.
Answer:
because some waste heat is always produced produced in a heat engine.
Explanation:
the fraction of heat input that is converted to a net work output is a measure of the performance of the heat engine and is called the thermal efficiency.Since the machine does not contain a source of energy ,nor can it store energy ,from this conversation of energy the power output of machine can never be greater than its input,so efficiency can be less than 100%.