# Search results

1. ### Speed of Light waves

1. Homework Statement A 5.9cm-thick layer of oil (n=1.46) is sandwiched between a 1.3cm -thick sheet of glass and a 2.4cm-thick sheet of polystyrene plastic (n=1.59) How long (in ns) does it take light incident perpendicular to the glass to pass through this 9.6cm -thick sandwich? 2...
2. ### How much heat will flow Thermodynamics

1. Homework Statement How much heat will flow in 30 minutes through a 2m X 2m section of concrete (k= 8.36 x 10^-1 J/s m *C) 20 cm thick if the inside temperature if 21*C and the outside temperature is -10*C? 2. Homework Equations Not sure but Q/t= {(kA/L} Tkelvin or Q/t=...
3. ### (Gravitational) Binding Energy

W=E2- E1 W=0- 1/2(MEv12)- (GMEMS)/r1 I don't know v1 so how can I solve for work?
4. ### Elastic Potential- Acceleration with springs

oops, so k=130.666 N/m
5. ### Elastic Potential- Acceleration with springs

Fy=may kx-mg=0 k=(mg)/x k=1306.666 N/m Fy=may kx-mg=may ay=(kx-mg)/m ay=9.79999 m/s2
6. ### Elastic Potential- Acceleration with springs

Fy=may kx-mg=may ay=(kx-mg)/m but k is not given....
7. ### Elastic Potential- Acceleration with springs

1. Homework Statement A 1.6kg mass is suspended from a spring inside a stationary elevator. The spring stretches 12cm. The elevator now accelerates upwards, and the spring extends a further 12cm. What is the elevator's acceleration? 2. Homework Equations Fy= may Ue= 1/2 (kx2) 3...
8. ### Mechanical Energy- Geosynchronous Orbit

1. Homework Statement What is the total mechanical energy of a 290 kg satellite in a geosynchronous orbit around the Earth? 2. Homework Equations W= K + UG where K= 1/2 (mv2) and UG= -(GmM)/r Fc= mac where ac= v2/r 3. The Attempt at a Solution I think the geosynchronous part...
9. ### (Gravitational) Binding Energy

1. Homework Statement How much work must be done to allow the Earth to escape the Sun? 2. Homework Equations E= K + UG where K= 1/2(mv2) and UG=-(GmM)/r W= E2- E1 Fc=mac 3. The Attempt at a Solution I have no idea where to start this, I missed the class where they took this up...
10. ### Mechanical Energy- Orbit

would it be, E= K + UG E= 1/2 (mv2) - (GmM)/r E= 1/2 m(GM/r) - (GmM)/r E= 2.377074x1010 J
11. ### Mechanical Energy- Orbit

so it would just be E= 1/2(GM/r) - (GM)/r E= -7819322.353 J
12. ### Mechanical Energy- Orbit

so, Fc= mac (GmM)/RE2=(mv2)/RE v2=(GM)/RE where RE is the radius of the earth then, E= K+ UG where K=1/2(mv2) and UG=-(GmM)/r2 and r= 2.55x107m (equal to 4 earth radii) so, E= 1/2(mv2) - (GmM)/r2 E= 1/2(GM)/RE) - (GM)/r2 E= 15633739.23 J
13. ### Work Energy- Tension

1. Homework Statement A 1.3kg stone is whirled in a vertical circle at the end of a 0.83m long string. The tension in the string at the top of the circle is 6.4N. What is the tension in the string when the stone is at the bottom of the circle? 2. Homework Equations Fc= mac...
14. ### Mechanical Energy- Orbit

1. Homework Statement What is the total mechanical energy of a 380kg satellite in a circular orbit 3.0 Earth radii above the surface? 2. Homework Equations W= E2- E1 E= 1/2 mv2- \frac{GmM}{r} 3. The Attempt at a Solution I'm not sure if the equations above are suitable to...
15. ### Dynamics- Net Gravitational Force

1. Homework Statement In a particular binary star system, Star A has a mass that is 28 times that of Star B. This distance between the stars is 34 AU (astronomical units). Find the location of the point in this star system where the net gravitational force on any mass would be zero. 2...
16. ### Archived Dynamics- Two Body Problems

1. Homework Statement Two blocks are stack on each other. The lower block has a mass of 6.8kg and μs=0.34 with the floor. The top block has a mass of 3.4kg and μs=0.65 between the two blocks. A force of 18N is being applied to the top box to the left. What maximum force can be applied to the...
17. ### Dynamics- No Friction

1. Homework Statement Find the normal force in terms of g, m, θ and α. There is no friction. a=0, θ≠α See first attachment for diagram 2. Homework Equations Fx=max 3. The Attempt at a Solution I drew a free body diagram including the forces; normal, mg, and |FA| (See...
18. ### Dynamics- Friction

the box wouldn't be accelerating, so would it be mg(μ_{s}cosθ-sinθ)=0 mgμ_{s}cosθ=mgsinθ μ_{s}cosθ=sinθ μ_{s}=tanθ θ=14.036
19. ### Dynamics- Friction

1. Homework Statement A box is halfway up a ramp. The ramp makes an angle, θ with the ground. What is the maximum value of θ before the mass will slip? μ_{s}=0.25 2. Homework Equations F_{x}=ma_{x} 3. The Attempt at a Solution I drew a free body diagram to show the forces...
20. ### Dynamics- Friction

1. Homework Statement A box is halfway up a ramp. The ramp makes an angle, θ with the ground. What is the maximum value of θ before the mass will slip? μ_{s}=0.25 2. Homework Equations F_{x}=ma_{x} 3. The Attempt at a Solution I drew a free body diagram to show the forces...
21. ### Newton's 3rd Law of Motion

1. Homework Statement A person is pushing against a wall, which just refuses to move. Fully and clearly describe how Newton's 3rd Law of Motion is affecting the person. 2. Homework Equations Newton's 3rd Law of motion is defined as "If one object exerts an action force on a second...
22. ### Centripetal Acceleration of amusement ride

I think the unit would be hertz? a_{c}=4∏^{2}r∫^{2} ∫^{2}=a_{c}/(4∏^{2}r∫^{2}) ∫=±√(a_{c}/(4∏^{2}r∫^{2})) ∫=±0.47hz So it would be 0.47hz?
23. ### Centripetal Acceleration of amusement ride

a_{c}=4∏^{2}r∫^{2} ∫^{2}=a_{c}/4∏^{2}r ∫=±√(a_{c}/4∏^{2}r) ∫=±0.47157 *calculator mixup on the previous answer*
24. ### Centripetal Acceleration of amusement ride

I'm getting 0.1465 for the frequency
25. ### Centripetal Acceleration of amusement ride

I think it's 1g=9.8m/s^{2} therefore 4.3g= 42.14m/s^{2}
26. ### Centripetal Acceleration of amusement ride

1. Homework Statement An amusement ride with a radius of 4.8m allows riders to experience 4.3g's of centripetal acceleration. What is the frequency of the ride? 2. Homework Equations a_{c}= 4∏^{2}r∫^{2} 3. The Attempt at a Solution a_{c}=4.3 r=4.8m ∫=? I keep getting...
27. ### Accelerated Motion in [2]- initial speed and launch angle

1. Homework Statement The range of a projectile is 483m, and it reached a maximum height of 65m. What were the initial speed and launch angle of the projectile? Assume the start and finish heights are equal. 2. Homework Equations 3. The Attempt at a Solution I just need a push...