Simple true and false questions

  • Thread starter Thread starter physicskid72
  • Start date Start date
AI Thread Summary
The discussion revolves around true or false questions related to kinetic energy and work. The first statement is deemed false, while the second is considered true, and the third is also marked false. Participants express uncertainty about the relevance of position above the Earth in gravitational contexts. The conversation highlights the complexities of understanding kinetic energy, particularly regarding variables in its formula.
physicskid72
Messages
13
Reaction score
0

Homework Statement



true or false


If there is no work there is no kinetic energy.

There has to be a change in velocity for there to be a change in kinetic energy.

when workiong with gravity, the difference in heights is important, the position above the Earth is not.

the sum of the kinetic energy and total energy is the total work.


Homework Equations





The Attempt at a Solution



1.) false
2.)true
3.)false

not sure on these please help
 
Physics news on Phys.org
You have 4 statements and 3 answers. For the gravity one, why do you think the position above the Earth is relevant?
 
kinetic energy formula has another variable than the velocity and the problem does not set it as constant so...
 
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

Comet orbiting a Star - True and False
Replies
6
Views
4K
Understanding the Energy Required to Lift Walls
Replies
8
Views
1K
Block sliding on a semicircular track with friction
Replies
10
Views
2K
Linear systems: Tmax = Umax is not making sense
Replies
4
Views
2K
The Total Energy of the Hydrogen Atom's Electron
Replies
2
Views
1K
Conservation of Energy with Gravitational Potential Energy
Replies
6
Views
2K
Temperature & Gas: Correct or Incorrect?
Replies
12
Views
1K
Motion in a Circle: True/False/Less/Greater/Equal
Replies
2
Views
5K
Potential Energy - 2D inelastic collision - ballistic pendulum
Replies
10
Views
2K
Energy Lost during elastic collision.
Replies
2
Views
1K

Hot Threads

Recent Insights

Back
Top