Force Problems.

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Presentation transcript:

Force Problems

Problem #1 80 N @ 70° above +x 60 N @ 25° above -x 75 N What is the resultant?

Force x y 60N -60cos25 60sin25 75N -75 80N 80cos70 80sin70 Totals -27.02 25.53

Problem #2 m = 15 kg μk = 0.6 120 N What is the acceleration?

Problem #3 m = 15 kg μk = 0.6 35° 250 N What is the acceleration?

Inclined Plane Problems (Ramps)

Setup

mgsinq mgcosq q

Find the Acceleration FN Ff X Y Weight 10(9.8)sin30 -10(9.8)cos30 mass = 10 kg mg 30o X Y Weight 10(9.8)sin30 -10(9.8)cos30 Friction -Ff Normal FN Total 49 - Ff FN – 84.9

Ramp Given mass m is at rest on a ramp that makes an angle θ with the horizontal, what is the minimum value of μs?

Combination What is the acceleration? M= 10 kg μk= 0.25 m = 3 kg 40o

Treat the masses and the string as one system