Haven't taken physics but I would assume if her friend is standing in front of her that you would add up the speeds and get 30 km/hr.
Answer:
B. 17.15 watts
Explanation:
Given that
Time = 10 seconds
height = distance = 0.7 meters
weight of sack = mg = F = 245 newtons
Power = work done/ time taken
Where work done = force × distance
Substituting the given parameters into the formula
Work done = 245 newton × 0.7 meters
Work done = 171.5 J
Recall,
Power = work done/time
Power = 171.5 J ÷ 10
Power = 17.15 watts
Hence the power expended is B. 17.15 watts
Formulas change from F to degree C : C = ( F - 32 )/1.8
so we have (77-32)/1.8 = 25 oC
ok done. Thank to me :>
Do u know Chinese ?if yes I can explain to u easily
Answer: 14.7kJ, 29.4kJ, 44.1kJ
Explanation:
<em>The gravitational potential energy is the energy that a body or object possesses, due to its position in a gravitational field. </em>
<em />
In the case of the Earth, in which the gravitational field is considered constant, the value of the gravitational potential energy 
will be:
Where 
is the mass of the object, 
the acceleration due gravity and 
the height of the object.
Knowing this, let's begin with the calculaations:
For m=3kg
For m=6kg
For m=9kg
