PHY 211 General PhysicsI Assignment 3 Due: October 24, 2017 Name: Student ID: Sc

Question

PHY 211 General PhysicsI Assignment 3 Due: October 24, 2017 Name: Student ID: Score: [Show your work for full credit Problem 1 Three forces F 30 N (45° above the horizon), F2- 80 N (30° below the horizon), and F, are applied on the block. The block moves leftward on the horizontal frictionless floor by 4 m. Find 10 N (a) work done by applied forces (b) work done by the weight and the normal force (c) net work done. F3 Fi 40 kg F2 Problem 2 A force F = (21 + 3 j) N is applied to a 10 kg block. The block slides on a horizontal frictionless floor from an initial position of r,-(-51 + 6 j) m to a final position of r,-(6i-10j) m. Find the work done by the applied force. Problem 3 A 6-kg block is moving on a horizontal frictionless floor with a speed of 4 m/s when a constant horizontal force F is applied to the block. The speed of the block increases to 10 m/s within a distance of 5 m. Find (a) initial and final kinetic energy. and (b) the applied force F Problem 4 A 0.50 kg block sliding on a horizontal frictionless surface with a speed of 2.5 m/s strikes a light spring that has a spring constant of 3000 N/m. (a) What is the total mechanical energy of the system (with respect to the horizontal surface)? (b) What is the maximum amount the spring will be compressed?

Explanation / Answer

F1 = 30 N (45 degrees above horizon)
F2 = 80 N (30 degrees below horizon)
F2 = 10 N
m = 40 kg

(a)

Fnety = F3 - F2 sin(30) + F1sin(45) - mg
Fnety =

W1 = F1cos(45)*(-4)
W1 = 30*cos(45)*-4 = -84.85

W2 = 80cos(30)*4 = 277.13

W3 = F3*0 = 0

(b)
Work done is 0 since the movement is horizontal

(c)
Net work done
W = W1 + W2 + W3
W = 277.13 - 84.85 + 0
W = 192.28

Please post separate questions for the other questions

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