2. A force of 20N acts on a particle of mass 2 Kg and displaces it by 5m at an angle 30°. What is the work done? a) 40J ) b) 50 J c) 100J

Given the position vector of the particle r(t)=(t+1)i+(t^2−1)j+2t k, find the particle's velocity and acceleration vectors at t=1

Aspring is used to stop a 50-kg package which is moving down a 20º incline. the spring has a constant k = 30 kn/m and is held by cables so that it is initially compressed 50 mm. knowing that the velocity of the package is 2 m/s when it is 8 m from the spring and neglecting friction, determine the maximum additional deformation of the spring in bringing the package to rest.

Consider two less-than-desirable options. in the first you are driving 30 mph and crash head-on into an identical car also going 30 mph. in the second option you are driving 30 mph and crash head-on into a stationary brick wall. in neither case does your car bounce off the thing it hits, and the collision time is the same in both cases. which of these two situations would result in the greatest impact force?