Answer:
3.8 secs
Explanation:
Parameters given:
Acceleration due to gravity, g = 9.8 
Initial velocity, u = 11.76 m/s
Final velocity, v = 49 m/s
Using one of Newton's equations of linear motion, we have that:

where t = time of flight of arrow
The sign is positive because the arrow is moving downward, in the same direction as gravitational force.
Therefore:

The arrow was in flight for 3.8 secs
Answer:
16 kg
Explanation:
M - container
m - oil mass
by definition of density ,
relative density is the ratio of the density of a substance to the density of water.
relative density = density/ density of water
density of oil = 1.2*1000 kgm⁻³ = 1200 kgm⁻³
1 Litre =10⁻³ m³
oil volume = 80 *10⁻³ m³
mass of oil = density * volume
= 1200*80*10⁻³
= 96 kg
Mass of container + mass of oil =112
mass of container = 112 - 96
= 16 kg
Answer:
v = 12.12 m/s
Explanation:
Given that,
The mass of the cart, m = 75 kg
The roller coaster begins 15 m above the ground.
We need to find the velocity of the cart halfway to the ground. Let the velocity be v. Using the conservation of energy at this position, h = 15/2 = 7.5 m

So, the velocity of the cart is 12.12 m/s.
150*4=600
So the answer is 600