Work done on cart
:
W
=
6000
J
Kinetic energy of cart
:
E
K
=
6000
J
Explanation:
Work done
W
is defined as the product of force
F
and distance
s
:
⇒
W
=
F
⋅
s
Let's substitute the values of
F
and
s
into the equation:
⇒
W
=
300
N
⋅
20
m
⇒
W
=
300
kg
⋅
m s
−
2
⋅
20
m
⇒
W
=
300
⋅
20
kg
⋅
m
2
s
−
2
⇒
W
=
6000
kg
⋅
m
2
s
−
2
∴
W
=
6000
J
The gain in kinetic energy
E
K
is the same amount as the work done moving the cart:
∴
E
K
=
6000
Answer:
Her usual rate is 0.8333 miles per hour.
Step-by-step explanation:
The velocity formula is given by:

In which d is the distance and t is the time.
She completed the first half of the walk 1 mi/h faster than usual
Her usual rate is v. 1mph faster is v + 1.
The second half of the walk 2 mi/h slower than the first half.
The first half is v + 1.
2mph slower is v + 1 - 2 = v - 1. Then
Total rate:
7.2 hours, and 6 miles. So
One half is v+1 and the other is v - 1. This is why each is multiplied by 0.5.



Her usual rate is 0.8333 miles per hour.
Subtract 3 first so it would be 7x=15
then divide by 7 so x would be approximately 2.14
Thx from the website http://goodcalculators.com/ratio-calculator/