Tom is at the gym. Tom lifts a 10kg weight using his bicep. If we consider the weight of Tom’s forearm to be 1.5kg, the distance from elbow to forearm as 40cm and the centre of mass as halfway between the elbow joint and forearm, calculate the force in toms arm.
A 105.7 N
B 107.5 N
C 103.5 N
D 105.3 N
Hey guys, can anyone explain how to solve this? The answer is B
can you explain what you did?
Where does the 430 come from? Surely it comes out as 43?
it’s a
10kg mass. Grav Force = 100N applied at 40cm from fulcrum or 0.4m
thus Torque is 40Nm
1.5kg mass. Grav Force = 1.5*10= 15N applied at 20cm from fulcrum or 0.2m
thus Torque is 3Nm
Net Torque in CW direction = 43Nm
To lift a weight you apply upward force through your hand thus the force req to lift the weight also takes place at 40cm or 0.4m
Thus Torque ACW should be equal to torque CW for a system
F*0.4 = 43
and thus Force is 430/4 or 107.5N
@nihantokar there you go!
