What is the weight of a 5kg object at the surface of the earth? A. 49N
B. 49kg
C. 5.0kg
D. 25N

When the force acting on an object points at least partially in the direction of the motion the work done is considered to be negative

What is the magnitude of the acceleration vector which causes a particle to move from velocity −5i−2j m/s to −6i+ 7j m/s in 8 seconds. answer in m/s.

What is a good example of instantaneous speed