Answer:
The slower runner is 1.71 km from the finish line when the fastest runner finishes the race.
Explanation:
Given;
the speed of the slower runner, u₁ = 11.8 km/hr
the speed of the fastest runner, u₂ = 15 km/hr
distance, d = 8 km
The time when the fastest runner finishes the race is given by;
The distance covered by the slower runner at this time is given by;
d₁ = u₁ x 0.533 hr
d₁ = 11.8 km/hr x 0.533 hr
d₁ = 6.29 km
Additional distance (x) the slower runner need to finish is given by;
6.29 km + x = 8km
x = 8 k m - 6.29 km
x = 1.71 km
Therefore, the slower runner is 1.71 km from the finish line when the fastest runner finishes the race.
Answer:
10.2 metres
Explanation:
Given that a ball is projected at an initial speed of 20.0 meter per second making an angle of 45.0 with horizontal. What is the maximum height it will reach?
Solution
To get the maximum height, let us use the formula
V^2 = U^2 sin^2ø - 2gH
At maximum height V = 0
U^2 sin^2ø = 2gH
Substitute all the parameters into the formula
20^2 ( sin 45 )^2 = 2 × 9.8 × H
400 × 0.5 = 19.6 H
Make H the subject of formula
H = 200 / 19.6
H = 10.204 metres.
Therefore, the maximum height reached by the projected ball is 10.2 metres.
Answer:
Energy: Kinetic, Sound, Thermal, gravitational, electric, light and nuclear
Explanation:
This exercise asks to clarify a little some important concepts
* Energy. It is the capable one that has the bodies to carry out a job.
* Kinetic energy. It is the energy due to the movement of objects
* sound energy. It is the energy due to the vibration of the atoms or molecules of the materials, it can be solid, liquid or gaseous
* Thermal energy. It is the energy due to movement of the particles
* Gravitational Energy. It is a configuration energy due to the height of the bodies with respect to a reference point
* Electric power. It is due to the movement of electric charges
* light energy. It is the energy that light carries due to the electric and magnetic fields that form it, it occurs throughout the electromagnetic spectrum
* Nuclear energy. It is the energy stored in the nucleus by the configuration and movement of protons and neutrons.
The object would have a centripetal acceleration <em>a</em> of
<em>a</em> = (12 m/s)² / (0.7 m) ≈ 205.714 m/s²
so that the required tension in the string would be
<em>T</em> = (0.5 kg) <em>a</em> ≈ 102.857 N ≈ 100 N
(rounding to 1 significant digit)
