Physics HW 2

PS115L Second Experiment Questions

1. If we give the cart an initial velocity instead of just letting it go, how would the plot of the position change? Hint: Look at the full equation of motion from equation (1) of the lab. You may use an excel plot with reasonable values for the different terms to illustrate the difference.

2. Identify at least two different physical reasons why your measured data might not have exactly matched you predicted result.

3. A ball is thrown upward with some initial velocity, what is its acceleration when it reaches its maximum height?

4. In this lab, you have learned that the rate of change of position with respect to time is velocity, and the rate of change of velocity with respect to time is acceleration. What's the rate of change of acceleration with respect to time?

5. Supposed the experiment is performed on the moon with minimal atmosphere, how would your theoretical and experiment result change as opposed to the one you perform on earth?

6. Is it possible for an object to have a positive (directional) velocity but a negative (directional) acceleration at the same time? If yes explain.

7. Briefly describe a situation when an object has zero acceleration but positive (directional) velocity.

8. Describe a situation when an object has negative acceleration with zero velocity.

Challenge Question

9. On the following plot, identify a point where the acceleration is at a maximum and a point where it is at a minimum. Also draw a plot of what the acceleration should look like.

10. Imagine a racing car  quickly approaching a corner, as the driver applies the brakes he/she feels his/her body moving forward and being pressed hard against the harness (racing seat belts). The driver then negotiates the corner and once through presses hard on the accelerator (gas pedal) he/she feels his/her body moving backward this time being pressed hard against the back of the seat. Describe the acceleration felt by the driver at corner entry and exit. be sure to include the direction of the acceleration and the causes (forces) associated.

Velocity vs time

0 0.31415926535897948 0.62831853071795818 0.9424777960769376 1.2566370614359179 1.5707963267948966 1.8849555921538761 2.199114857512857 2.5132741228718345 2.8274333882308142 3.1415926535897931 3.4557519189487724 3.7699111843077531 4.0840704496667284 4.3982297150257104 4.7123889803846923 5.0265482457436717 5.3407075111026483 5.6548667764616276 5.9690260418206096 6.2831853071795845 1 0.95105651629515364 0.80901699437494712 0.58778525229247369 0.30901699437494795 6.1257422745431173E-17 -0.30901699437494784 -0.58778525229247358 -0.80901699437494701 -0.95105651629515364 -1 -0.95105651629515364 -0.80901699437494756 -0.5877852522924738 -0.30901699437494812 -1.837722682362934E-16 0.30901699437494778 0.58778525229247336 0.80901699437494701 0.95105651629515364 1

Time (s)

Velocity (m/s)