- #1
Zsmitty3
- 46
- 3
1. An .8kg block is held in place against the spring by a 67 N horizontal external force. The external force is removed, and the block is projected with a v1=1.2. upon separation for the spring. The block then descends a ramp and has a velocity v2=1.9 m/s at the bottom. The track is frictionless up to that point. The block enters a rough section B, extending to E. The coefficient of friction over this section is .39. The velocity of the block is v3=1.4 m/s at C. The block moves on to D, where it stops. The spring constant of the spring is closest to:
1100N/m 3900N/m 2600N/m 1600N/m 2000N/m
2. It seems like a lot to take in. I have a couple thought about how to go about it but not sure if any would work. There's also a diagram of the situation included.
3. First I started simple and thought maybe we didn't need all that and tried just using F=.5kx^2 but we don't know x. So then I proceeded trying to use Conservation of Energy. At the top there would be some PE and the KE would be .576. after the drop, the PE would be 0 and the KE goes up to .5*.8*1.9^2=1.444. Since there is no friction, the initial PE must have been 1.444-.576=868N. That gets me to the spring with the PE and KE known but I have no clue from there because there's also PE in the spring along with the gravitational PE. I'm not sure if I need to include the friction part somehow. Thanks!
1100N/m 3900N/m 2600N/m 1600N/m 2000N/m
2. It seems like a lot to take in. I have a couple thought about how to go about it but not sure if any would work. There's also a diagram of the situation included.
3. First I started simple and thought maybe we didn't need all that and tried just using F=.5kx^2 but we don't know x. So then I proceeded trying to use Conservation of Energy. At the top there would be some PE and the KE would be .576. after the drop, the PE would be 0 and the KE goes up to .5*.8*1.9^2=1.444. Since there is no friction, the initial PE must have been 1.444-.576=868N. That gets me to the spring with the PE and KE known but I have no clue from there because there's also PE in the spring along with the gravitational PE. I'm not sure if I need to include the friction part somehow. Thanks!