The position of a 2.75×105N training helicopter under test is given by r⃗ =(0.020m/s3)t3i^+(2.2m/s)tj^−(0.060 m/s2)t2k^.

Find the net force on the helicopter at t=5.0s.

Express your answer in terms of i^, j^, k^. Use the 'unit vector' button to denote unit vectors in your answer. Express your coefficient using two significant figures.

Afeather of mass 0.001 kg falls from a height of 2 m. under realistic conditions, it experiences air resistance. based on what you know about friction, what can you say about the kinetic energy of the feather as it reaches the ground? acceleration due to gravity is g = 9.8 m/s2. a. ke < 0.0196 j b. ke = 00196 j c. je = 0 j d. ke > 0.0196 j

Within a pendulum, as potential energy decreases, energy increases. a. heat b. kinetic c. frictional d. gravitational

The particles that are found in the nucleus of an atom are