Which the following statements about the force of friction is true?

a. friction acts in the direction opposite to weight.

b. friction acts in the same direction as the normal force.

c. friction acts in the same direction as weight.

d. friction acts in the direction opposite to an object's motion.

who knows how to do this?

An astronaut in space cannot use a scale or balance to weigh objects because there is no gravity. but she does have devices to measure distance and time accurately. she knows her own mass is 77.4 kg , but she is unsure of the mass of a large gas canister in the airless rocket. when this canister is approaching her at 3.50 m/s , she pushes against it, which slows it down to 1.30 m/s (but does not reverse it) and gives her a speed of 2.60 m/s . what is the mass of the canister?