Answer:
An electric current is a stream of charged particles, such as electrons or ions, moving through an electrical conductor or space. It is measured as the net rate of flow of electric charge through a surface or into a control volume. ... In electric circuits the charge carriers are often electrons moving through a wire.
Given that,
Initial velocity , Vi = 0
Final velocity , Vf = 40 m/s
Acceleration due to gravity , a = 9.81 m/s²
Distance can be calculated as,
2as = Vf² - Vi²
2 * 9.81 *s = 40² - 0²
s = 81.55 m
For half height, that is, s = 40.77m
Vf= ??
2as = Vf² - Vi²
2 * 9.81 * 40.77 = Vf² - 0²
Vf² = 800
Vf = 28.28 m/s
Therefore, speed of roller coaster when height is half of its starting point will be 28 m/s.
Answer:3.67 m/s
Explanation:
mass of block(m)=2 kg
Velocity of block=6 m/s
spring constant(k)=2 KN/m
Spring compression x=15 cm
Conserving Energy
energy lost by block =Gain in potential energy in spring

![2\left [ 6^2-v_2^2\right ]=2\times 10^3\times \left [ 0.15\right ]^2](https://tex.z-dn.net/?f=2%5Cleft%20%5B%206%5E2-v_2%5E2%5Cright%20%5D%3D2%5Ctimes%2010%5E3%5Ctimes%20%5Cleft%20%5B%200.15%5Cright%20%5D%5E2)

-- As far as we know, the forces on the wheelbarrow are balanced.
-- That tells us that the net force on the wheelbarrow is zero, just
as if there were no forces acting on it at all.
-- That tells us that the wheelbarrow's acceleration is zero ... its
speed and direction of motion are not changing.
-- That tells us that the wheelbarrow is moving in a straight line
at a constant speed. It's very possible that relative to us, the speed
may be zero, but we can't tell that from the given information.
It means that velocity not only has a size, but it also has a direction.
Some other vector quantities are force and acceleration.
They have sizes and directions.
Temperature, cost, and weight are quantities with only size and no direction.
Those are called "scalar" quantities.