Problem 8: A skateboarder with mass m, = 47 kg is standing at the top of a ramp which is h, = 4.4 m above the ground. The skateboarder then jumps on his skateboard and descends down the ramp. His speed at the bottom of the ramp is vf= 6.4 m/s. Part (a) Write an expression for the work, Wr, done by the friction force between the ramp and the skateboarder in terms of the variables given in the problem statement. Expression : Wf= Select from the variables below to write your expression. Note that all variables may not be required. cos(0), sin(0), a, ß, n, Q, 0, d, g, hy, mg, P, t, Vf, Wf Part (b) The ramp makes an angle 0 with the ground, where 0 = 30°. Write an expression for the magnitude of the friction force, f,, between the ramp and the skateboarder. Expression : F%= Select from the variables below to write your expression. Note that all variables may not be required. cos(0), sin(0), a, ß, A, Q, 0, d, g, hy, m,, P, t, Vf, Wf

4. Consider again the situation given in Problem 1. (a) Find the center-of-mass of the system made up of m, and m,, taking the origin to be at P. (b) Draw a free body force diagram with the all of the mass (m, + m,) concentrated at this center-of-mass position. (c) Find the torque about P due to (m, + m2) concentrated at this center of mass position. How does this result compare to (d) in Problem 1? [We will make use of this technique often for certain types of future problems.]

1. Give a real world example of the following. A. Something that can be modeled as a vector. B. Something that can be modeled as a scaler.

Please ans part b only

Just need D and E A) 0.0517 m/s^2 B) 5.37 N C) 4.8076 N

#2 A-C

1. Determine the x, y, and z components of the 900 N force shown in Figure 1. 22 900 N 65° y 20⁰ 35⁰ Figure 1 750 N 25° x

5. For the figure below, what are the magnitudes and directions of the following cross products? a. ₁ x ma = ? b. 7₂ x mã = ? C. ₁ XF = ? d. 7₂ x F = ? 0.6 m 7₁ TEN 72 0.6 m ma 0.8 m 0.8 m |ma|= 600 N |F|= 400 N

If the speed of the skateboarder at point A is v= 1.2 m/s, what is her speed at point B? Assume that friction is negligible. Express your answer using appropriate units. V Templates Symbols undo redo reset keyboard shortcuts help L Value Units