Missing graph. I attach it in the answer.
In a uniformly accelerated motion, the velocity at time t is given by:

where a is the acceleration and t is the time.
Given the previous equation, if we plot v(t) versus t, we find a straight line; moreover, a (the acceleration) represents the slope of the curve.
Looking at the graph, we see that when the time goes from 10 s to 20 s, the velocity increases from 4 m/s to 6 m/s. Therefore the slope of the curve is

and this corresponds to the acceleration.
So, the correct answer is <span>
0.2 m/s2.</span>
Answer:
11.714 kW
Explanation:
Here is the complete question
A loaded ore car has a mass of 950 kg and rolls on rails with negligible friction. It starts from rest and is pulled up a mine shaft by a cable connected to a winch. The shaft is inclined at 34.0∘ above the horizontal. The car accelerates uniformly to a speed of 2.25 m/s in 10.5 s and then continues at constant speed. What power must the winch motor provide when the car is moving at constant speed?
Solution
Since the loaded ore car moves along the mine shaft at an angle of θ = 34° to the horizontal, if F is the force exerted on the cable, then the net force on the laoded ore car is F - mgsinθ = ma where mgsinθ = component of the car's weight along the incline, m = mass of loaded ore car = 950 kg and a = acceleration
F = m(a + gsinθ)
When the car is moving at constant speed, a = 0
So F = m(a + gsinθ) = F = 950(0 + 9.8sin34) = 5206.1 N
Since it continues at a constant speed of v = 2.25 m/s, the power of the winch motor is P = Fv = 5206.1 N × 2.25 m/s = 11713.7 W = 11.714 kW
Answer:
150J
Explanation:
work output/work input=100%
so just make work output the subject
The Answer that makes the most sense is C.