an object 8.25 cm from a lens creates a virtual image of magnification 2.40 what is the focal length of the lens (mind your minu
1 answer:
You might be interested in
Answer:
the power that must be supplied to the motor is 101.45 hp
Explanation:
Given that,
The weight of elevator = 1000lb
The motor exerts a constant force of 500 lb on the cable
The load has been hoisted s = 15 ft starting from rest
The motor has an efficiency of e = 0.65
According to the equation of motion:
F = ma
To calculate the output power:
P(out) = F. v
P(out) = 3 (500) * 21.98
P(out) = 32970 lb.ft/s
As efficiency is given and output power is known, we can calculate the input power.
ε = P(out) / P(in)
0.65 = 32970 / P(in )
P(in) = 50,723 lb.ft/s
P(in) = 50,723 / 500 hp
= 101.45 hp
the power that must be supplied to the motor is 101.45 hp
Missing figure: find it in attachment.
Answer:
Force D
Explanation:
In order to answer the question, let's keep in mind that the force of gravity on an object on Earth is the attractive force exerted by the Earth on the object; its direction is always downward (towards the Earth's centre), and its magnitude is given by
F = mg
where m is the mass of the object and g is the acceleration of gravity.
It follows immediately that in the figure, the force of gravity is the only force acting downward: therefore, force D.
The other forces are called:
Force A: thrust (it is the forward force generated by the engines)
Force B: lift (it is the upward produced by the aerodynamics of the wings)
Force C: air resistance (it is the backward force due to the friction between the air and the surface of the plane)
