Answer:
0.031 W
Explanation:
The power used is equal to the rate of work done:

where
P is the power
W is the work done
t is the time taken to do the work W
In this problem, we have:
W = 900 J is the work done by the motor
t = 8 h is the time taken
We have to convert the time into SI units; keeping in mind that
1 hour = 3600 s
We have

And therefore, the power used is

Answer:
m = 4.4 × 10³ kg
Explanation:
Given that:
The total yearly energy is 4.0 × 10²⁰ J
The amount of mass that provides this energy can be determined by using the formula:
E = mc²
where;
c = speed of light in free space = (3 × 10⁸)
4.0 × 10²⁰ = m × (3 × 10⁸)²

m = 4.4 × 10³ kg
The speed of the runner is 300 m /38 seconds. You can simplify this answer to be about 7.9 m/s
Answer:
distance between the dime and the mirror, u = 0.30 m
Given:
Radius of curvature, r = 0.40 m
magnification, m = - 2 (since,inverted image)
Solution:
Focal length is half the radius of curvature, f = 
f = 
Now,
m = - 
- 2 = -
= 2 (2)
Now, by lens maker formula:


v =
(3)
From eqn (2):
v = 2u
put v = 2u in eqn (3):
2u = 
2 = 
2(u - 0.20) = 0.20
u = 0.30 m
Answer:51.44 units
Explanation:
Given
x component of vector is 
y component of vector is 
so position vector is

Magnitude of vector is


|r|=51.44 units
Direction

vector is in 2nd quadrant thus

