What Is the Average Power Output of a Race Car's Motor During Acceleration?

  • Thread starter Thread starter k0k
  • Start date Start date
  • Tags Tags
    Energy Power
AI Thread Summary
The discussion focuses on calculating the average power output of a 1250-kg race car accelerating from rest to 30.0 m/s in 4.00 seconds on a frictionless surface. The relevant formulas include power (P = E/t), force (F = ma), and kinetic energy (Ek = 1/2 mv^2). Participants clarify that the change in energy should be kinetic, and a mistake was made by incorrectly using 15 m/s instead of the correct 30 m/s in calculations. The correct average power output is determined to be 141 kW. The conversation emphasizes the importance of accurate values in physics calculations.
k0k
Messages
13
Reaction score
0
A 1250-kg race car accelerates uniformly from rest to 30.0m/s in 4.00s on a horizontal surface with no friction. What must be the average power output of its motor? (Ans:141kW)

--
P=E/t
F=ma
Ek=1/2mv^2

--

P=E/t
P=Ek/t
=(.5X1250kgX15.0m/s^2) / (4.00s)
=35156.25 W

How exactly do I start this off? I assume that the change in energy should be kinetic only, right?.
 
Physics news on Phys.org
k0k said:
A 1250-kg race car accelerates uniformly from rest to 30.0m/s in 4.00s on a horizontal surface with no friction. What must be the average power output of its motor? (Ans:141kW)

--
P=E/t
F=ma
Ek=1/2mv^2

--

P=E/t
P=Ek/t
=(.5X1250kgX15.0m/s^2) / (4.00s)
=35156.25 W

How exactly do I start this off? I assume that the change in energy should be kinetic only, right?.

I think you would have had the correct answer had you not replaced the given 30 m/s with 15 m/s.
 
OH, okay got it now. : D
Thanks
 

Thread 'Struggling to understand the concept of this question (ice cube in water optics question)'

TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
View full post »
Thread 'Variable mass system : water sprayed into a moving container'

Thread 'Variable mass system : water sprayed into a moving container'

Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
View full post »

Similar threads

How Do You Calculate Race Car Acceleration and Power Output?
Replies
20
Views
2K
Avg Power in a Rotational Energy/Work Problem
Replies
6
Views
1K
Calculating Average Power and Energy Consumption for a Heater
Replies
10
Views
2K
What is the power input of a motor pulling up an elevator?
Replies
3
Views
3K
Worksheet Problem about Power (average power of a car accelerating up a hill)
Replies
2
Views
2K
Car acceleration kinematics give average power
Replies
5
Views
2K
Calculate power to have the car at a certain speed
Replies
4
Views
2K
Calculate Avg Power Output for 75kg Person Walking 100ft in 3min
Replies
9
Views
2K
What Is the Power Output of a Car Accelerating from Rest in First Gear?
Replies
4
Views
2K
Ratio of Power between Two Cars
Replies
14
Views
2K

Hot Threads

Recent Insights

Back
Top