Please help with the following physics problems.
1) A student pushes on a swinging door to leave a class. How much torque is exerted in each of the following cases if the force exerted is 50 N?
A – The student pushes perpendicular to the door at the end farthest from the hinges (a distance of 80 cm).
B – The student pushes at an angle of 60 degrees to the door at the end farthest from the hinges.
C – The student pushes perpendicular to the door at the end where hinges are located.
2) How much tension does your bicep exert in order to support your forearm held out horizontally if the weight of your forearm is 12N? Assume the centre of mass of your lower arm is located 15 cm from the elbow joint and the bicep is located 5 cm from the elbow joint.
3) How much tension does your bicep exert to support not only your arm, but also a 12N weight in your hand? Assume the weight is located 20 cm from the centre of mass of the lower arm.