Answer:
88.18 W
Explanation:
The weight of the boy is given as 108 lb
Change to kg =108*0.453592= 48.988 kg = 49 kg
The slope is given as 6% , change it to degrees as
6/100 =0.06
tan⁻(0.06)= 3.43°
The boy is travelling at a constant speed up the slope = 7mi/hr
Change 7 mi/h to m/s
7*0.44704 =3.13 m/s
Formula for power P=F*v where
P=power output
F=force
v=velocity
Finding force
F=m*g*sin 3.43°
F=49*9.81*sin 3.43° =28.17
Finding the power out
P=28.17*3.13 =88.18 W
Answer:
A force must s applied to a wall or roof rafters to add strength and keep the building straight and plumb
Answer:
The company found the cost of the required photovoltaic cells too expensive.
Explanation:
Solar energy can be used as an alternative source of supply for fuel. Solar energy is a renewable source of energy, that is it keeps on replenishing every day. Also solar energy does not require a lot of maintenance.
The cost required is starting a solar system is very high because one needs to buy solar panel, photovoltaic cells for batteries, inverters and so on.
From the question, the company decided against solar energy for the time being. This means that probably in the future they might consider it. Therefore it is as a result of the economic situation of the company that they have not set up a solar system because the cost of the required photovoltaic cells too expensive.
Complete Question
The cars of a roller-coaster ride have a speed of 19.0 km/h as they pass over the top of the circular track. Neglect any friction and calculate their speed v when they reach the horizontal bottom position. At the top position, the radius of the circular path of their mass centers is 21 m, and all six cars have the same mass.V = -18 m What is v?X km/h
Answer:

Explanation:
Velocity 
Radius 
initial velocity u
Generally the equation for Angle is mathematically given by




Generally
Height of mass



Generally the equation for Work Energy is mathematically given by

Therefore



Answer:
Mechanical Efficiency = 83.51%
Explanation:
Given Data:
Pressure difference = ΔP=1.2 Psi
Flow rate = 
Power of Pump = 3 hp
Required:
Mechanical Efficiency
Solution:
We will first bring the change the units of given data into SI units.

Now we will find the change in energy.
Since it is mentioned in the statement that change in elevation (potential energy) and change in velocity (Kinetic Energy) are negligible.
Thus change in energy is

As we know that Mass = Volume x density
substituting the value
Energy = Volume * density x ΔP / density
Change in energy = Volumetric flow x ΔP
Change in energy = 0.226 x 8.274 = 1.869 KW
Now mechanical efficiency = change in energy / work done by shaft
Efficiency = 1.869 / 2.238
Efficiency = 0.8351 = 83.51%