Will someone tell me if i am right?
if a system is entirely isolated, which of the following conditions apply?
a. q = 0, w = 0
b. q > 0, w < 0
c. q > 0, w = 0
d. q = 0, w < 0
i thinks its b?

A1,200 kg car is accelerated at 3.7 m/s2. what force was needed to produce this acceleration? a. 4,440 n b. 324.3 n c. 4,388 n d. 304.3 n

What does si stand for,when referring to a system of measurement

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?