Answer:
14.5 m/s up the incline
Explanation:
Take up the incline to be positive and down the incline to be negative.
Impulse = change in momentum
J = Δp
∫ F dt = mΔv
∫ (F cos θ – mg sin θ) dt = m (v – v₀)
∫ (40t cos θ – mg sin θ) dt = m (v – v₀)
20t² cos θ – mgt sin θ = m (v – v₀)
20(5)² cos 15° – (15)(9.8)(5) sin 15° = 15 (v – -5)
292.73 = 15 (v + 5)
v = 14.5
The velocity of the block after 5 seconds is 14.5 m/s up the incline.
