This question involves the concept of the conservation of energy.
(a) The child's speed halfway will be "12.13 m/s".
(b) The child's speed three-fourth way will be "14.86 m/s".
(a)
Using the <em>law of conservation of energy</em>:
Potential Energy Lost = Kinetic Energy Gained
where,
v = speed = ?
g = acceleration due to gravity = 9.81 m/s²
h = height lost = halfway = height/2 = 15 m/2 = 7.5 m
Therefore,
<u>v = 12.13 m/s</u>
<u />
(b)
Using the <em>law of conservation of energy</em>:
Potential Energy Lost = Kinetic Energy Gained
where,
v = speed = ?
g = acceleration due to gravity = 9.81 m/s²
h = height lost = three-fourth way down = 
Therefore,
<u>v = 14.86 m/s</u>
<u />
Learn more about the <em>law of conservation</em> of energy here:
brainly.com/question/20971995?referrer=searchResults
The attached picture shows the <em>law of conservation of energy</em>.
Answer:
A kilowatt (kW) is a unit of power.
Explanation:
The power of an object is given by :
Here,
E is the energy required
t is time
The SI unit of power is Watts and the SI unit of energy is Joule. the commercial unit of energy is kilowatt per hour.
Option (1) : A kilojoule (kJ) is a unit of power is incorrect.
Option (2) : A gigawatt (GW) is a unit of energy is incorrect.
Option (3) : A watt (W) is a unit of energy is incorrect.
Option (4) : A kilowatt x hour per year (kWh/yr) is a unit of energy is incorrect.
Option (4) : A kilowatt (kW) is a unit of power is correct.
Hence, the correct option is (d).
Answer:
K.E = 1.28 × 10^-17 KeV
Explanation:
Given that a particle accelerator at CERN can accelerate an electron through a potentialdifference of 80 kilovolts.
To Calculate the kinetic energy (in keV) of the electron, let us first find the electron charge which is 1.60 × 10^-19C
The kinetic energy = work done
K.E = e × kV
Substitute e and the voltage into the formula
K.E = 1.60 × 10^-19 × 80
K.E = 1.28 × 10^-17 KeV
Therefore, the kinetic energy is approximately equal to 1.28 × 10^-17 KeV
F(in) x d(in)= F(out)x d(out)
A machine has a mechanical advantage of 5.
F(out )= 5xF(in)300 newtons
F(in) = 300 N
F(out)= 5xF(in) = 5x300 N
= 1500 N
Work in = Work out = 3000 N x m3000
N x m = F_in x d_ind_in = 3000 Nxm / F_in = 3000 N x m / 300 N = 10 m3000 Nxm = F_out x d_out d_out = 3000 Nx m / F_out = 3000 N x m / 1500 N = 2 m
