Answer:D
Explanation:Electric power=I*I*R
=12*12*100
=14400watts
Answer:
vB = 15.4 m/s
Explanation:
Principle of conservation of energy:
Because there is no friction the mechanical energy is conserve
ΔE = 0
ΔE : mechanical energy change (J)
K : Kinetic energy (J)
U: Potential energy (J)
K = (1/2)mv²
U = m*g*h
Where :
m: mass (kg)
v : speed (m/s)
h : hight (m)
Ef - Ei = 0
(K+U)final - (K+U)initial =0
(K+U)final = (K+U)initial
((1/2)mv²+m*g*h)final = ((1/2)mv²+m*g*h)initial , We divided by m both sides of the equation:
((1/2)vB² + g*hB = (1/2 )vA²+ g*hA
(1/2) (vB)² + (9.8)*(14.7) = 0 + (9.8)(26.8 )
(1/2) (vB)² = (9.8)(26.8 ) - (9.8)*(14.7)
(vB)² = (2)(9.8)(26.8 - 14.7)
(vB)² = 237.16

vB = 15.4 m/s : speed of the cart at B
Answer:
We have to show surface area
,with few conditions that is by considering Force
and Pressure
to be respectively.
Explanation:
The atmospheric pressure is
on Earth's surface.
The magnitude of the force exerted on a person by the atmosphere is
.
Now to calculate surface area we can find it from
and re-arranging it to.

So plugging the values,
Surface area 
Hence from the above calculations we can say that surface area is
.
So the surface area of an average person can be said to have
, using the concept of pressure and force.
Answer:
The ladder is 3.014 m tall.
Explanation:
To solve this problem, we must use the following formula:
v = x/t
where v represents the woman’s velocity, x represents the distance she climbed (the height of the ladder), and t represents the time it took her to move this distance
If we plug in the values we are given for the problem, we get:
v = x/t
2.20 = x/1.37
To solve this equation for x (the height of the ladder), we must multiply both sides by 1.37. If we do this, we get:
x = (2.20 * 1.37)
x = 3.014 m
Therefore, the ladder is 3.014 m tall.
Hope this helps!
Answer:
9.22 s
Explanation:
One-quarter of a turn away is 1/4 of 2π, or π/2 which is approximately 1.57 rad
Let t (seconds) be the time it takes for the child to catch up with the horse. We would have the following equation of motion for the child and the horse:
For the child: 
For the horse: 
For the child to catch up with the horse, they must cover the same angular distance within the same time t:



t = 25.05 or t = 9.22
Since we are looking for the shortest time we will pick t = 9.22 s