How Much Work is Required to Accelerate a Mass from 2 m/s to 60 m/s?

  • Thread starter Thread starter Ockonal
  • Start date Start date
  • Tags Tags
    Speed Work
AI Thread Summary
To calculate the work required to accelerate a mass of 6×10⁴ kg from 2 m/s to 60 m/s, the relevant equation is the change in kinetic energy, expressed as ΔKE = 0.5m(v₂² - v₁²). An initial attempt to calculate the work resulted in a negative value, indicating a misunderstanding in the application of the formula. The correct approach involves using A_res = m/2 × (V₂² - V₁²) to find the positive work done. The discussion highlights the importance of correctly applying kinetic energy principles in physics problems. The issue was resolved with the correct formula, leading to an accurate calculation of work.
Ockonal
Messages
30
Reaction score
0

Homework Statement


What work needs to be done to change body speed with mass 6×10⁴ kg from 2 m/s to 60 m/s?


Homework Equations


A = mgh
A = FS
A = mv²/2


The Attempt at a Solution


A₁ = mV₁² / 2
A₂ = mV₂² / 2
A_res = A₂ - A₁;

A_res = m/2 × (V₁² - V₂²)
A_res = 3×10⁴ × (4 - 3600)

The result is negative and too big. Is that right?
 
Physics news on Phys.org
Ockonal said:

Homework Statement


What work needs to be done to change body speed with mass 6×10⁴ kg from 2 m/s to 60 m/s?

Homework Equations


A = mgh
A = FS
A = mv²/2

The Attempt at a Solution


A₁ = mV₁² / 2
A₂ = mV₂² / 2
A_res = A₂ - A₁;

A_res = m/2 × (V₁² - V₂²)
A_res = 3×10⁴ × (4 - 3600)

The result is negative and too big. Is that right?
The change in kinetic energy is positive: \Delta KE = \Delta (mv^2/2) = .5m(v_2^2-v_1^2)

What units does your answer have? Why do you think the result is too big?

AM
 
Ok, nevermind. Solved it, thanks.
 
A_res = m/2 × (V₂² - V₁²)
 
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 »

Thread 'Egg Drop Challenge! Need ideas for winning designs'

I was thinking using 2 purple mattress samples, and taping them together, I do want other ideas though, the main guidelines are; Must have a volume LESS than 1600 cubic centimeters, and CAN'T exceed 25 cm in ANY direction. Must be LESS than 1 kg. NO parachutes. NO glue or Tape can touch the egg. MUST be able to take egg out in less than 1 minute. Grade A large eggs will be used.
View full post »

Similar threads

Earth's Accel.: Is 10^(-22)m/s^2 Correct?
Replies
3
Views
1K
Solving for Work Done When Accelerating a Mass
Replies
3
Views
773
Minimizing Friction for a Ball in a Rough Bowl: Accelerations and Velocity
2
Replies
90
Views
9K
Amusement Park Centripetal Force Question.
Replies
11
Views
5K
Coefficient of Friction question for a cart going down a wooden ramp
Replies
18
Views
3K
Finding slip-off angle for mass off of sphere?
Replies
7
Views
1K
Simple Work Problem Disagreeing with Kinematics
Replies
4
Views
1K
Maximum height a block reaches after separating from a curved moving ramp
Replies
8
Views
2K
Distribution of Energy when work is done on a system of 2 masses connected by a spring
Replies
17
Views
2K
When is the acceleration due to gravity negative and when is it positive?
Replies
13
Views
5K

Hot Threads

Recent Insights

Back
Top