Answer:
The speed of the cart decreases
Explanation:
The track is frictionless, so we can consider the cart as isolated system (no external forces acting on it): therefore, the momentum of the cart is conserved
where m is the mass and v the speed of the cart.
When it starts raining, some water falls into the cart: this means that the mass of the cart, m, increases. But we said that the momentum, p, must remain constant: in order for that to happen, this means that the speed of the cart, v, must decrease (because the relationship is an inverse relationship, so if m increases, v must decrease).
Explanation:
1. Distance, d = 5 m
Time, t = 10 s
Speed = distance/time
2. Mass, m = 10 kg
Acceleration, a = 3 m/s³
Force, F = mass (m) × acceleration (a)
F = 10 × 3
= 20 N
3. Mass, m = 7 kg
Height, h = 4 m
Potential energy, E = mgh
E = 7 × 9.8 × 4
E = 274.4 J
Hence, this is the required solution.