# Search results

1. ### Speed of light questions

hm... becuase I have a spacetime diagram modeling this answer and it seems that it is only supposed to be 12 seconds....
2. ### Speed of light questions

btw, this is all from signal sender's frame of reference.
3. ### Speed of light questions

the ship is moving in the positive direct and is at 0 ls when t = 0
4. ### Building a car without a mousetrap! i'm desperate!

use styrofoam (or something equally light), stick a fan on the back. Add wheels. Voila.

a fan?
6. ### Speed of light questions

Homework Statement A signal (traveling at the speed of light) is sent from -4 ls (light seconds) towards a moving spaceship traveling at 0.866c. How long does it take for the signal to reach the ship? Homework Equations I'm pretty sure its t=(delta)D/c-v But I continue to get the...
7. ### Friction problem again Okay today is not my day

but I'm not given the train's acceleration... am I missing something here =/?
8. ### Friction problem again Okay today is not my day

Homework Statement A passennger is standing without slipping in a forward accelerating train. The coeffeciant of the feet and the floor is 0.47. Determine the maximum required acceleration of the train relative to the track if the passenger is not to slip Homework Equations F=ma The...
9. ### Simple but unsure, compound questions

omg, how did I miss that 0_0 thank you, everything is 100% clear now =P
10. ### Simple but unsure, compound questions

isn't the equation (mu)mg? mu = F/N right? So therefore F=(mu)N -> F = (mu)mg?
11. ### Incline and Firction (again!)

Solved, thanks guys
12. ### Incline and Firction (again!)

thats the thing though... it doesn't give you the mass. It ONLY gives you the force of kinetic friction and the initial speed
13. ### Incline and Firction (again!)

Homework Statement A skier on a slope inclined at 4.7 degrees from the horizontal starts down the slope with an initial speed of 2.7m/s. The coefficient of friction is 0.11. Determine how far the skier will slide before coming to a rest. Homework Equations Fnet=ma F(f) = (mu)N The...
14. ### Simple but unsure, compound questions

Basically: givens v(1) = 0m/s F(t) = 21N (31 degree) (mu kinetic) = 0.5 (mu static) = 0.55 a = 0m/s^2 X component Fnet=ma F(t) - F(f) = ma F(t) = (mu)Mg m = F(t) / (mu)g m= 18N / 0.55*9.8 m = 3.3kg Y Component F(net) = ma F(t) = Fg F(t) = m/g m = 21Sin31 / 9.8 m =...
15. ### Simple but unsure, compound questions

A boy is pulling on a box at a 31 degree angle using 21N of force. The box remains stationary. The co-efficient of static friction is 0.55. What is the minimum mass? When I use the component method to solve this problem, do I need to calculate the mass for both the Horizontal and the Vertical...
16. ### FDB for TENNIS

thank you so much
17. ### FDB for TENNIS

lol, so to sum it up: force exerted on ball = force exerted on racquet. However, ball flies away extremely quickly and racquet doesnt is becaue racquet is heavier and therefore according to Newton's second low, it doesnt accelerate as much (and also since the racquet is anchored to the player's...
18. ### FDB for TENNIS

yea, the equal and opposite force excerted on the racquet stated by the 3rd law.
19. ### FDB for TENNIS

F(a) = applied force F(n) = Normal force umm, yea sry. I was typing a bit too quickly. Third and Second law. nono, i mean if a tennis racquet was to hit a tennis ball. Would the applied force and normal force be equal or would applied force be larger?
20. ### FDB for TENNIS

Homework Statement for an FDB of an tennis ball hitting the racquet. Is the F(a)=F(n) or is F(a) larger then F(n). The Attempt at a Solution I think that F(a) = F(n). According to Newton's second law, they both receive the same force, however since the tennis ball has less mass...
21. ### Confusing (but surely simple) gravity problem

Lol, thank you soooo much (again!)
22. ### Confusing (but surely simple) gravity problem

Homework Statement An exceptional vertical jump from rest would raise a person 0.80m off the ground. To do this, what constant force would a 70kg person have to exert against the ground? Assume the person lowers himself 0.20m prior to jumping and remains in a standing position while in the...
23. ### A falling man

ahh, ic. Thank you montoyas and Dr. Jekyll. I understand it now.
24. ### A falling man

we havent learned that yet... is it possible to only solve this problem with F=ma and the kinematic equations
25. ### A falling man

[SOLVED] A falling man Homework Statement a 90kg man falls (freefalls) 10m, when he lands, his legs buckle and he goes down another 23cm. What was the average force he exerted on the ground? Homework Equations M = 90k a = 9.8 m/s^2 The Attempt at a Solution from freefall to...
26. ### Deriving F=ma? a vs F?

ahh, ic thank you very much. That might explain why i never got anything by searching up alpha on google :P can you please tell me what it is called?
27. ### Deriving F=ma? a vs F?

so would i derive a vs F or a vs m in the same fashion as: a (alpha) x a (alpha) y a (alpha) z a = xyz
28. ### Deriving F=ma? a vs F?

I knew i should have paid more attention in class =/ anyways, We have been studying newton's second law. And I have a question on my lab that asks for me to "derive equation for a (acceleration) vs F (force) and a (acceleration) vs m (mass)" a vs F and a vs M are two graphs which we did...