Answer:
(a) 2.5 m/s
(b) 37.5 KJ
Explanation:
(a)
From the law of conservation of momentum, Initial momentum=Final momentum
and making 
the subject then
and since 
is initial velocity of car, value given as 4 m/s, 
is the initial velocity of the three cars stuck together, value given as 2 m/s and 
is the final velocity which is unknown. By substitution
(b)
Initial kinetic energy is given by
Final kinetic energy is given by
The energy lost is given by subtracting the final kinetic energy from the initial kinetic energy hence
Energy lost=350-312.5=37.5 KJ
This question is poorly stated, but I assume you mean what conditions are needed. It would have to be cold outside, correct?
No additional force is required because it's already going downhill
Answer:
Velocity (v) is a vector quantity that measures displacement (or change in position, Δs) over the change in time (Δt), represented by the equation v = Δs/Δt. Speed (or rate, r) is a scalar quantity that measures the distance traveled (d) over the change in time (Δt), represented by the equation r = d/Δt.
Explanation:
Speed has the dimensions of distance divided by time. The SI unit of speed is themetre<span> per second, but the most common unit of speed in everyday usage is the kilometre per </span>hour<span> or, in the US and the UK, miles per </span>hour<span>. For air and marine travel the knot is commonly used.</span>
