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1.) In the figure provided, a 283 kg crate is released from rest and hits the gr

ID: 1783401 • Letter: 1

Question

1.) In the figure provided, a 283 kg crate is released from rest and hits the ground 2.36 m below after 6.09 s. What is the mass of the crate to the left of the pulley? Assume the rope and pulley are massless. ( please use as many numbers as possible during calculations then in the end 3 sig figs). I appreciate it a lot !

2.)

In the figure provided, two crates are sliding down a ramp. If the crate at the top has a mass of 37.7 kg and the other has a mass of 75.4 kg, what is the tension in the string? Assume the string is massless.

Explanation / Answer

(1) First find out the value of the acceleration of the system by using the expression -

s = ut + (1/2)*a*t^2

=> 2.36 = 0 + 0.5*a*6.09^2

=> a = 2.36 / (0.5*6.09^2) = 0.127 m/s^2

Write the force - mass acceleration and suppose T is the tension in the cord and a is the accleration of the mass -

T - mg = ma

=> T = mg + ma

for bigger mass -

283g - T = 283a

put the value of T -

283g - mg - ma = 283a

=> 283(g-a) = m(g+a)

put the value of a -

=> 283(9.81-0.127) = m(9.81+0.127)

=> m = (283*9.683) / 9.937 = 275.8 kg.

Answer in three significant figures = 276 kg.