Answer:
2100 J
Explanation:
Parameters given:
Force acting on the object, F = 420 N
Distance moved by object, d = 5m
The change in kinetic energy of an object is equal to the work done by a force acting on the object:
W = F * d
∆KE = F * d
∆KE = 420 * 5
∆KE = 2100 J
Given:
Force of person pushes against the wagon= F = 420 N
Distance = d = 5.0 m
When you accelerate an object, you are doing work against inertia. It is proven that work equals the change in kinetic energy of the object.
therefore, W = ΔKE
where,
W is the work done against the resistance of inertia
ΔKE is the change in kinetic energy (Δ is Greek letter capital delta)
Also, W = F x d
∴∆KE = F x d
∆KE = 420 x 5
The change in kinetic energy for the wagon is 2100 J
125 m
m = 3kg
v = 50m/s
u = 0m/s
a = +g = 10m/s²
s = H = ?
using the formula,
v² = u² + 2as
50² = 0² + 2(10)(H)
2500 = 20H
H = 2500/20
H = 125m
A or B
D. a concave mirror
