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
Answer:
1.03 m/s
Explanation:
I'm too lazy to write the explanation down but my teacher graded this and it was right
Where r is the radius of balloon.
Here mass of woman = 68 kg
Mass of air displaced by a balloon with volume V = 1.29*V
Mass of helium inside balloon = 0.178*V
Total mass to be lifted by balloon = 68 +0.178*V
Buoyant force = 1.29V-0.178V=1.112V
So we have 1.112 V = 68+ 0.178*V
0.934 V = 68
V = 72.81 
\frac{4}{3} \pi r^{3}[/tex]= 72.81
r = 2.59 m
So radius of helium balloon = 2.59 m
Answer:
2.5 m/s²
Explanation:
Given,
Initial speed ( u ) = 10 m/s
Final speed ( v ) = 20 m/s
Time ( t ) = 4 seconds
To find : Acceleration ( a ) = ?
Formula : -
a = ( v - u ) / t
a = ( 20 - 10 ) / 4
= 10 / 4
= 5 / 2
a = 2.5 m/s²
Therefore,
The acceleration of the scooter is 2.5 m/s²
