工程科學應力應變題 Ex1~Ex2 ?

Question

Acceleration due to gravity = 10 ms-2;

Calculation steps should be clearly shown;

Answers correct to two decimal places.

1. Determine the resultant and its position of the system of forces 200N15度角, 150N100度角, 120N-120度角 and 300N-50度角.

2. ABCD is a light inextensible string passing round a smooth pulley C and a force F (N) applied at B in a direction perpendicular to the string maintains equilibrium. Determine the magnitude of F and the angle BCD.

Answer 1

Favorite Answer

1) resolve the forces into x, y direction

x- direction

200sin15 + 300sin50 + 150cos10 + 120cos30

=533N

y- direction

200cos15 + 300cos50 - 150sin10 - 120sin30

=300N

resultant

(533^2+300^2)^0.5

=612N

bearing

90-tan^-1(300/533)

=60.6 deg

2) sorry,

there seems to be no any weight, how comes a force is needed to balance?

Source(s): myself