Explanation:
Initial time, t₁ = 2:30 pm
Final time, t₂ = 2:30:45
We need to find the motion of students in terms of time. Final time is 45 seconds more than the initial time.
Change in time,
Hence, this is the required solution.
The value of gravitational acceleration of a body on Earth is 9.8 meters/second2. The gravitational potential energy for a 1.00
1 answer:
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Answer:
<em>a) 318.2 W/m^2</em>
<em>b) 2.5 x 10^-4 J</em>
<em>c) 1.55 x 10^-8 v/m</em>
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Explanation:
Power of laser P = 1 mW = 1 x 10^-3 W
exposure time t = 250 ms = 250 x 10^-3 s
If beam diameter = 2 mm = 2 x 10^-3 m
then
cross-sectional area of beam A = = (3.142 x
)/4
A = 3.142 x 10^-6 m^2
a) Intensity I = P/A
where P is the power of the laser
A is the cros-sectional area of the beam
I = ( 1 x 10^-3)/(3.142 x 10^-6) = <em>318.2 W/m^2</em>
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b) Total energy delivered E = Pt
where P is the power of the beam
t is the exposure time
E = 1 x 10^-3 x 250 x 10^-3 = <em>2.5 x 10^-4 J</em>
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c) The peak electric field is given as
E =
where I is the intensity of the beam
E is the electric field
c is the speed of light = 3 x 10^8 m/s
= 8.85 x 10^9 m kg s^-2 A^-2
E = = <em>1.55 x 10^-8 v/m</em>
Answer:
F = 2 × 10⁻³ N
Explanation:
Given:
frequency, f = 2400 MHz
Height, h = 25cm = 0.25 m
Area of the base, A = 30 cm x 30 cm = 900 cm² = 0.09 m²
Energy of the microwave, E = 0.50 mJ = 0.5 x 10⁻³ J
Now, the time taken by the wave from top to the base, t = h/c
here, c is the speed of the light
thus,
t = 0.25/(3 x 10⁸) = 8.33 x 10⁻¹⁰ s
The radiation pressure = Intensity/c
now, the intensity is given as:
I = Power/ area
also,
Power = Energy/ time = 0.5 x 10⁻³ J/8.33 x 10⁻¹⁰ s = 600000 W
thus,
I = 600000 W/ 0.09 m² = 6666666.6 W/m²
substituting the value in the formula for pressure due to radiation, we have
= 6666666.6 W/m²/(3 x 10⁸)
also
pressure = Force/ area
thus,
Force/ area = 6666666.6 W/m²/(3 x 10⁸)
or
Force (F) = (6666666.6 W/m² × 0.09 m²)/(3 x 10⁸)
or
F = 2 × 10⁻³ N
According to the second law of motion, force is the product of mass times acceleration. If we were to solve for the force, we would need the acceleration and the mass.
Acceleration was not given in the problem, but we can solve for it by using the velocity and the time because by definition, acceleration is the change in velocity over time.
The initial velocity is 16.0m/s because it is the first recorded time. The final is 0 m/s or the last recorded velocity. The time we will use is 2.0 s because it is the time the change in velocity occurred.
Now that we have acceleration, we can now solve for the Force. Again Force is the product of mass and acceleration.
or 
The force is -2N. Now if you are looking for the magnitude of the force then you can just put 2N.
The negative sign indicates the direction of the force, if it is negative this means that the force applied was in the opposite direction.
Acceleration was not given in the problem, but we can solve for it by using the velocity and the time because by definition, acceleration is the change in velocity over time.
The initial velocity is 16.0m/s because it is the first recorded time. The final is 0 m/s or the last recorded velocity. The time we will use is 2.0 s because it is the time the change in velocity occurred.
Now that we have acceleration, we can now solve for the Force. Again Force is the product of mass and acceleration.
The force is -2N. Now if you are looking for the magnitude of the force then you can just put 2N.
The negative sign indicates the direction of the force, if it is negative this means that the force applied was in the opposite direction.