We can do this with the conservation of momentum. The fact it is elastic means no KE is lost so we don't have to worry about the loss due to sound energy etc.
Firstly, let's calculate the momentum of both objects using p=mv:
Object 1:
p = 0.75 x 8.5 = 6.375 kgm/s
Object 2 (we will make this one negative as it is travelling in the opposite direction):
p = 0.65 x -(7.2) = -4.68 kgm/s
Based on this we know that the momentum is going to be in the direction of object one, and will be 6.375-4.68=1.695 kgm/s
Substituting this into p=mv again:
1.695 = (0.75+0.65) x v
Note I assume here the objects stick together, it doesn't specify - it should!
1.695 = 1.4v
v=1.695/1.4 = 1.2 m/s to the right (to 2sf)
Complete Question
The complete question is is shown on the first uploaded
Answer:
The elastic potential energy at point B is 
The kinetic energy at point D is 
Explanation:
Looking at the given point we can observe that mechanically energy(i.e potential and kinetic energy ) is conserved and it value is 
So at point B
KE at point B is 50J
So 
Now at point D
at point D is 25J
So 
Answer: The correct option is (d)
lava flows built up from the ocean floor by multiple, summit and flank eruptions
Explanation:
Piles of baseltic lava flows built up from the ocean floor by multiple summit and flank eruptions describes seamounts and islands of the deep ocean basins.
It transforms it to mechanical
Answer:
Explanation:
Using Snell's law
n₁ sinθ₁ = n₂ sinθ₂
for 420 nm wavelength
where n₁ = 1.00 ( refractive index of air) and θ₁ = 30° n₂ = 1.660
1.00 × sin 30° = 1.660 sinθ₂
sinθ₂ = 0.3012
θ₂ = sin⁻¹ 0.3012 = 17.53°
for 690 nm wavelength
n₁ sinθ₁ = n₂ sinθ₂
sinθ₂ = 0.5 / 1.630
θ₂ = sin⁻¹ 0.3067 = 17.86°
the angle between the two beam = 17.863° - 17.53° = 0.333°
