Added potential energy = (mass) x (gravity) x (height)
or
Added potential energy = (weight) x (added height)
If you need to lift a 15N box 3m straight up, you have to increase its potential energy by (15 N) x (3 m) = 45 Joules .
Where is that added potential energy supposed to come from ? You could use an electric winch, a steam engine, a gasoline-powered motor, thousands of hamsters running on little treadmills that are are connected to the main pulley somehow, or your own arm muscles. But howEVER you do it, you have to provide <em>45 Joules</em> of WORK in order to increase the potential energy of the box by just that much.
Answer:
Minimum time interval (t2)=0.90 SECONDS
Explanation:
- coefficient of friction for employees footwear = 0.5
- coefficient of friction for typical athletic shoe = 0.810
- frictional force = coefficient of friction X acceleration due to gravity X mass of body
- Acceleration due to gravity is a constant = 9.81 m/s
- Let frictional force for employee footwear = FF1
- Let frictional force for athletic footwear =FF2
FF1 = O.5 X 9.81 X mass of body
= 4.905 x mass of body
FF2 = 0.810 X 9.81 X mass of body
= 7.9461 x mass of body
The body started from rest there by making the initial velocity zero ( u = 0)
From d= ut + 1/2 a x 
- d =
x a x
.....................................i
where d= distance and it is given as 3.25m
- F =ma ...................................ii
making acceleration subject of the formula from equation ii
- a =

Making t subject of formula from equation (i)
- t=

where
-
= 4.905
=7.9461
Let
- t1 = minimum time taken for frictional force for employee foot wear
- t1 =
=1.15 seconds
- t2 =
= 0.90 seconds
THANK YOU
Explanation:
Because they change the direction of force and multiply the effort.
They increase the rate of doing work.
So, MA of first class lever can be one or greater than one or less than one
A). No. The medium is glass.
B). Yes. There is no material between the satellite and Earth,
only vacuum.
C). No squared. The rings are not electromagnetic waves, and
the material is water.
D). No squared. Sound is not an electromagnetic wave, and
the material is air.
(i)1.5cm
(ii)4.5cm
(iii)10cm