Answer:
a). P=11.04kW
b). Pmax=11.38 kW
c). Wt=6423.166kJ
Explanation:
The power of the motor when the speed is constant is the work in a determinate time.

The work is the force the is applicated in a distance so
W=F*d
replacing:
and
determinate distance in time is velocity so
a).


b).
The maximum power must the motor provide, is the maximum force with the maximum speed of the motor in this case
The first step is find the acceleration so

The maximum force is when the car is accelerating so

so the maximum force is the maximum force by the maximum speed

c).
The total energy transfer without any friction is the weight move in the high axis y in this case, so is easy to know that distance
W=m*g*h
h=Length*sin(33.5)
W=m*g*Length*sin(33.5)
W=950 kg*9.8* 1250m*sin(33.5)
W=6423166.667 kJ
W=6423.166 kJ
Energy = power × time
1800 = 300 × time
time = 1800 ÷ 300 = 6 s
Hope it helped!
Tools we'll use:
-- Gravitational potential energy = (mass) x (gravity) x (height)
-- Kinetic energy (of a moving object) = (1/2) (mass) x (speed)²
When the pendulum is at the top of its swing,
its potential energy is
(mass) x (gravity) x (height)
= (5 kg) x (9.8 m/s²) x (0.36 m)
= (5 x 9.8 x 0.36) joules
= 17.64 joules .
Energy is conserved ... it doesn't appear or disappear ...
so that number is exactly the kinetic energy the pendulum
has at the bottom of the swing, only now, it's kinetic energy:
17.64 joules = (1/2) x (mass) x (speed)²
17.64 joules = (1/2) x (5 kg) x (speed)²
Divide each side by 2.5 kg:
17.64 joules / 2.5 kg = speed²
Write out the units of joules:
17.64 kg-m²/s² / 2.5 kg = speed²
(17.64 / 2.5) (m²/s²) = speed²
7.056 m²/s² = speed²
Take the square root
of each side: Speed = √(7.056 m²/s²)
= 2.656 m/s .
Looking through the choices, we're overjoyed to see
that one if them is ' 2.7 m/s '. Surely that's IT !
_______________________________
Note:
The question asked for the pendulum's 'velocity', but our (my) calculation
only yielded the speed.
In order to describe a velocity, the direction of the motion must be known,
and the question doesn't give any information on exactly how the pendulum
is hanging, and how it's swinging.
We know that at the bottom of its swing, the motion is completely horizontal,
but we have no clue as to what direction. So all we can discuss is its speed.
Answer:
w = 25.05 rad / s
, α = 0.7807 rad / s²
, θ = 1972.75
Explanation:
This is a kinematic rotation exercise, let's start by looking for the acceleration when the engine is off
θ = w₀ t - ½ α t²
α = (w₀t - θ) 2/t²
let's reduce the magnitudes to the SI system
w₀ = 530 rev / min (2pi rad / 1 rev) (1 min / 60 s) = 55.5 rad / s
θ = 250 rev (2pi rad / 1 rev) = 1570.8 rad
let's calculate the angular acceleration
α = (55.5 39 - 1570.8) 2/39²
α = 0.7807 rad / s²
having the acceleration we can calculate the final speed
w = w₀ - ∝ t
w = 55.5 - 0.7807 39
w = 25.05 rad / s
the time to stop w = 0
0 = wo - alpha t
t = wo / alpha
t = 55.5 / 0.7807
t = 71.09 s
the angle traveled
w² = w₀⁹ - 2 α θ
w = 0
θ = w₀² / 2α
let's calculate
θ = 55.5 2 / (2 0.7807)
θ = 1972.75