Answer:
Work done, W = 6 J
Explanation:
It is given that,
Force of gravity acting on the book, weight of the book is 15 N
We need to find the work done in lifting the book straight up for a distance of 0.4 meters.
The weight of the book is acting in downward direction and the book is lifted straight up, it means angle between them is 180 degrees. Work done is given by :

So, the magnitude of work done in lifting the book is 6 joules.
Answer:
10kg
Explanation:
Let PE=potential energy
PE=196J
g(gravitational force)=9.8m/s^2
h(change in height)=2m
m=?
PE=m*g*(change in h)
196=m*9.8*2
m=10kg
Answer:
4 A
Explanation:
V = IR, where V=voltage, I=current, R=resistance. This is Ohm's Law. (remember that for units V = volts, Ω = ohms, A = amperes.)
V = IR
12 V = I * 3 Ω
12/3 = I
<u>I = 4 A</u>
Answer:
346 * 10⁶ m
Explanation:
The force of gravity of the earth that will cancel the the force of gravity exerted by the moon will be equal to each other
Let
be the force of gravity exerted by the earth
and let
be the force of gravity exerted by the moon
According to Newton's law of universal gravitation, the force of attraction between two different masses, m₁ and m₂ separated by a distance, d, is given by:

Mass of the earth, 
Mass of the moon, 
Mass of the satellite, 
...............................(1)
The earth and the moon are separated by a distance, 3.844 * 10⁸ m
............................(2)
Equating equations (1) and (2)


Factorising out 

Solving for d in the quadratic equation above:
d = 346 * 10⁶ m