# Search results

1. ### Minimum speed at the circular track

Thanks a lot. Why didn't consider the force at the top?
2. ### Minimum speed at the circular track

Homework Statement What is the minimum speed of the car must have at the top of the loop? There are three methods. I would like to know which method or answer is correct. Please see attached file. Homework Equations Please see attached file. The Attempt at a Solution Please...
3. ### Conservation momentum for y- axis

No. We could not use Law of conservation of momentum for falling objects because of the external force acting on it. I don't want the answer. I want correct method.
4. ### Conservation momentum for y- axis

Please see examiner report.Pls. see attachment.
5. ### Conservation momentum for y- axis

If the time duration of the collision was nonzero, the collision force would have to be specified as a function of time. If it was a nice constant force you could work out the motion during the collision beginning with an F = ma formula for each mass. Looks complicated. The answer would not...
6. ### Conservation momentum for y- axis

Homework Statement A ball P of mass m kg is dropped from a point A, which is 2 m vertically above a point B on a horizontal floor. After P hits the floor at B, it rebounds and hits another ball Q, of the same mass, which has also been dropped from A. The impact between the two balls is...
7. ### Two bodies attracting via gravitation

When I calculate the problems for collision, e=(speed of separation)/(speed of approach) If two bodies are moving opposite directions, relative velocity is v1+v2. If two bodies are moving same direction, relative velocity is v2-v1. After collision two bodies need to separate. It...
8. ### F = m x a, but what if velocity is constant (making a zero)?

I think before collision speed of truck is constant but after collision speed is not constant. So it has acceleration. Now we can consider force.
9. ### (M1 x 1)+(M2 x2) / M1+M2

You took the wrong value. We don't know xb and yb We know centre of mass where is it. x(bar) (or) xc=2, y(bar) or yc=5.5 Use xc=(m1x1+m2x2)/(m1+m2) . You can find x2. yc formular is similar as xc. You can find y2.
10. ### Simple coefficient of friction problem

Read the problem again. Constant speed!!! Equilibrium condition!!

12. ### Velocity of a particle when acceleration based on displacement

Where is the problem?
13. ### Help with inclined plane

Draw the diagram for initial and final position for the object. Use law of conservation of energy at the top and distace d from the bottom.
14. ### Revolutions and angular speeds

You forgot to do square for v0. So calculate again.
15. ### Torque problem

Wow!!Take the axis at point P is very easy to calculate. Thanks .
16. ### Find the velocity of each object after the collision

Yes, right. You have previous for momentum. You can easy to get the answer.
17. ### Find the velocity of each object after the collision

Here your first equation, it is correct. 607 g cm/s = 28 g v1f + 5 g v2f Second equation is Before collision total KE= After collision total KE
18. ### Find the velocity of each object after the collision

Hello Mandy, You said subtracted 33 from each side but v1f and v2f are not the same you cannot do like this. You should use law of conservation of momentum and law of conservation of kinetic energy to solve 2 unknown problem.
19. ### Very Tough Question. Can you answer?

Please access this website and observe the multimedia. http://www.physicsclassroom.com/mmedia/kinema/avd.cfm
20. ### Finding recoil speed given force, mass, and velocity

You know weight of the rifle. Find mass of the rifle. Before firing, rifle and bullet haven't moved yet. You can consider their velocities before firing.
21. ### Conservation of momentum of astronaut in her space suit

I think you need to consider projectile motion concept.
22. ### Did I do this angular acceleration problem right?

Calculate again. Your answer is wrong. rev convert to radian, minute convert to second. Unit conversion is very important. Becareful / * sign .
23. ### Formula for radial acceleration

radial acceleratio is same as centripetal accelaration. aR=v2/r=w2r=wv Good luck!!
24. ### Perfect inelastic collison

I mean after collision, two objects stuck together. So velocities are the same but problem didn't mention direction is angle theta. I think angles are not the same before and after collision.
25. ### Perfect inelastic collison

Do you know the direction (angle) after collision?
26. ### Stopping Grinding Wheel

Use summation torque= I(alpha) For summation torque=F(r)-Ffr(r)
27. ### Stopping Grinding Wheel

wheel is a solid disc. I=0.5 mr2 How many forces acting on the wheel? When you consider torque, you may consider applied force and frictional force.
28. ### Unbanked and banked Curves problem

Two forces acting on the roller coaster. Normal force , weight, frictional force.
29. ### Block sliding along a looped track

At the top,direction of normal force and weight are towards the centre and at the bottom, opposite direction. velocity depends on the point for circular track. weight is same as any point but normal force is not the same. At the top normal force value is very small and at the bottom, it's value...
30. ### Hooke's Law and constants

a. F=ma F=(5.8kg)(9.8m/s2) F=56.84N F=-kx 56.84N = -k (.425m - .330m) k=598.3 N/m or 0.598 kN/m b. F=-kx 170N = -598.3 N/m x x= 284.3m I think part (a) is correct. Part (b) is in correct. Two applied forces are same magnitude and opposite directions. It will cancel each...