Chapter 4: Motion in a Plane

Q1. A projectile is launched at 30° with velocity 40 m/s. Find the range.

Solution

R = v²sin2θ/g = (40²)(sin60°)/10
= 1600 × (√3/2)/10 = 80√3 ≈ 138.6 m

Q2. Find the cross product of A = 2⋂⃗i + 3⋂⃗j and B = ⋂⃗i - ⋂⃗j.

Solution

A × B = |⋂⃗i ⋂⃗j ⋂⃗k; 2 3 0; 1 -1 0| = ⋂⃗k(-2-3) = -5⋂⃗k