Question

A 125 Frisbee is thrown from a point 0.90 m above the ground with a speed of 12.00 m/s. When it has reached a height of 2.70 m, its speed is 10.0478 m/s. How much work was done on the Frisbee by its weight?
-2.21 J

How much of the Frisbee's mechanical energy was dissipated by air drag (positive value)?

NEED. HELP. WITH THIS ONE

Answer 1

here,

the mass of Frisbee , m = 125 g = 0.125 kg

the speed of Frisbee is v1 = 12 m/s at h1 = 0.9 m

the speed of Frisbee is v2 = 10.0478 m/s at h2 = 2.7 m

the work done on Frisbee by its weight , Wg = m * g * ( h2 - h1) * cos(180)

Wg = 0.125 * 9.81 * ( 2.7 - 0.9) * (-1) J

Wg = - 2.21 J

the Frisbee's mechanical energy was dissipated by air drag , ME = MEi - MEf

ME = (m * g * h1 + 0.5 * m * v1^2) - (m * g * h1 + 0.5 * m * v1^2)

ME = 0.125 * ((9.81 * 0.9 + 0.5 * 12^2) - (9.81 * 2.7 + 0.5 * 10.0478^2)) J

ME = 0.48 J