how do i find retarding force?

Question

An automobile engine develops 30 hp in moving the automobile at a constant speed of 50 mile/h. What is the average retarding force due to such things as wind resistance, interval friction and tire friction?

Answer 1

You will need to work out the units. But the basic way to answer this question is as follows:

You are given the speed, V.
You are also given the power, P.
P= Work/Time
Work=Force* Distance.
Thus
Power=Force*Distance/TIme.
Distance/time is the speed. So you can say that the Power is simple Force*Speed.
You have the speed, and the power. so you can now solve for force.

Because the auto is moving at a constant speed, there is no acceleration, which means the force pushing the auto is the same as the forces going against it. Thus, your force that you solve for should be the same as the retarding force that you are seeking.
Good luck.

Answer 2

if the speed is constant, there is no net acceleration, and the force retarding the car is equal to the force accelerating the car

in other words, the engine energy pushing the car forward is equal to the friction energy pushing backward, so the car neither speeds nor slows but stays at a constant velocity

that part is clear, lets see if I can remember how to apply the arithmetic

30 hp can be converted to ft-lbf/sec (550 ft-lbf/sec per hp)
16500 ft-lbf/sec

now, traveling at 50 mph (or 73.3 ft/sec)

you can calculate the force 16500/73.3=225 lbf

the force is 225 lbs

so the effect of the drag is the same as lifting 225 lbs

Answer 3

Hmmm, ..., a retarding rigidity interior the image voltaic gadget, eh? convinced that would want to be the Hysteria Channel! instead of being champions of the training procedure they're helping decrease human intelligence by using the servile adherence to dooms day programming. ok, so the reply you're possibly searching for is: GRAVITY. Gravity from all gadgets in our image voltaic gadget impression the operation of the image voltaic gadget. now and again it may "retard" or decelerate the structure of an merchandise by ability of area however it may also boost up or in some severe situations "seem" to repulse gadgets.