A few days ago

physics questions?

1. A 75N force is applied to a wrench handled at a point that is 20cm from the axis of rotation. What is the torque due to this force if the force makes an angle of (a) 90degrees b) 75degrees c) 45 degrees with the handle?

2. Why does an upright person who is carrying a heavy suitcase in one hand will tend to automatically have the other hand extended some distance away from body?

3. For safety an extension ladder that leans against a wall should make a small angle w/ vertical. Why?

Top 1 Answers
A few days ago

Favorite Answer

1. The formula you need is t=FxR where F=force applied, R=wrench length. It’s a cross product so unless the force is at 90 degrees to the wrench axis, not all of it is used to create torque, only the component of the force that’s perpendicular to the wrench will produce torque, so

a)t = 75kg*m/(s)^2 * 0.2m = 15 kg*m^2/s^2

b)t = 75N * 0.2m * sin(75) = 14.5

c) t = 75N * 0.2m * sin(45) = 10.6

P.S., I should add that SI unit for torque is N*m, I didn’t have to convert Newtons into kg*m/s^2