Answer:
Explanation:
Kinetic energy involves motion so something that is not moving has zero kinetic energy.
Potential energy does not involve motion and is based on position in a field like gravity and magnetic.
Answer:
n = 2.25 x 10¹⁴ electrons/s
Explanation:
The amount of electric current is defined as the electric charge passing through an area per unit time. Hence:
I = q/t
where,
I = Current
q = amount of charge
t = time interval
but,
q = ne
therefore,
I = ne/t
where,
n = no. of electrons
e = charge on single electron = 1.6 x 10⁻¹⁹ C
t = 1 s (for electrons passing per second)
I = Current = 36 μA = 3.6 x 10⁻⁵ A
Therefore,
3.6 x 10⁻⁵ A = n(1.6 x 10⁻¹⁹ C)/1 s
n = (3.6 x 10⁻⁵ A)/(1.6 x 10⁻¹⁹ C)
<u>n = 2.25 x 10¹⁴ electrons/s</u>
Answer:
112J (3 s.f.)
Explanation:
KE= 1/2mv^2
where KE is kinetic energy, m is the mass in kg, and v is the velocity (or speed to take it simply) in m/s.
KE= 1/2(6)(6.1^2)
KE= 111.63
KE= 112J (3s.f.)
187500 Joules of work must be done to the 3000 kg car to change its speed from 10 m/s to 15 m/s.
Explanation:
Work is the measurement of the force on an object that overcomes a resisting force (such as friction or gravity) times the distance the object is moved. If there is no distance, there is no work, no matter what the effort.
Work done = Force * displacement
When you apply enough force on an object to overcome a resistive force, such that you move that object, you are doing work on that object. There is a relationship between that work and mechanical energy.
When an object is accelerated, you are doing work against inertia, such that the work equals the change in kinetic energy of the object.
Work done = Change in K.E
In the given case:
mass = m = 3000 kg
initial velocity = v₁ = 10 m/s
final velocity = v₂ = 10 m/s
Work = W = (1/2)m(v₂)² - (1/2)m(v₁)²
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Answer:
6logs
Explanation:f
First finding the volume of the logs
V= π/4d²l
= 0.098m³
So number of logs will be
Weight of 2 boys + weight of log = buoyancy force.
So
2( 400)+ N ( Mlog x g) = density of water x volume displaced x g
2(400) = N x 0.098x 1000x 9.8 x 0.9- 0.75* 1000
N= 5.5 which is approx 6logs