An object's position in a given coordinate system is described by the vector r = t2 i - (3t + 3) j. assume the object moves without air resistance. einaaa@berkeley. edu 25%

part (a) what is the object's displacement between times t1 = 1 s and t2 = 3 s? write your answer in component form. δr = 8 i - 6 j ✔ correct!

The object´s displacement vector is Δr =  8i - 6 j  

Explanation:

Hi there!

The position vector is given by the following function:

r = t²i - (3t + 3) j

Let´s find the position of the object at time t1 and t2:

At t1 = 1 s:

r1 = (1)² i - (3 · (1) + 3 )j

r1 = 1 i - 6 j

At t2 = 3 s:

r2 = (3)² i - (3 · (3) + 3) j

r2 = 9 i - 12 j

The displacement is calculated as follows:

displacement = Δr = final position - initial position = r2 - r1

r2 - r1 = 9 i - 12 j - (1 i - 6 j)

r2 - r1 = 9 i - 12 j - 1 i + 6 j

r2 - r1 = 8 i - 6 j

The object´s displacement vector is Δr =  8i - 6 j  

b. lifting dumbbell weight at 20-degree angle from the body after a 45-degree angle

the force represented by vector a is normal force. if the hockey puck is moving to the right, when it is hit with a significant force by the hockey stick the puck will move off in a different direction. correct on edge.