Answer:
It’s trueee bcz the empty cart has less mass.
Answer:
For example, when a person walk
Explanation:
The force of friction is a resistive force that opposes the motion of objects. It is produced by the contact between two surfaces: since the surfaces are not perfectly smooth, there are "microbumps" that cause a resistive force in the relative motion of the two surface.
This force is evident, for example, when we try to push a crate along the floor: as we push forward, there is a resistive force acting in the opposite direction, and this force is the force of friction.
The force of friction is in the direction opposite to the motion of the object, so in general it tends to slow down the motion of the object over the surface.
However, there is a particular case in which instead friction helps in accelerating the object.
This scenario is when a person walks: in fact, the foot of the person pushes against the floor (backward), and as a result, the floor "pushes" forward with the force of friction, which helps therefore the person to move forward. In fact, the force of friction is the force that allows us to walk forward: without the force of friction, we could not walk (think about how difficult it is to walk over an icy surface: this is because the force of friction on an icy surface is almost zero!)
Answer:
Forces 1 and 2 cannot have equal magnitudes.
Force 1 exceeds force 2.
Explanation:
Numbering the given statements:
- The force of the horse pulling on the cart.
- The force of the cart pulling on the horse.
- The force of the horse pushing on the road
.
- The force of the road pushing on the horse.
- When a horse pulls a cart along a flat road starting from the state of rest, the horse applies a force on the ground in downward-back direction diagonally and as its reaction it moves forward. During this action there is also a reaction force by the road on the horse which exceeds the force of the horse on the ground and as a result the horse moves forward.
- For pulling the cart the horse applies the force on the cart in the forward direction and as a reaction the cart applies a force on the horse in the backward direction which is less than the force of the horse on the cart resulting in the forward motion of the cart along with the horse.
Answer:
![\frac{dB}{dt} = 3.49 *10^{6} \ \ T/s](https://tex.z-dn.net/?f=%5Cfrac%7BdB%7D%7Bdt%7D%20%3D%203.49%20%2A10%5E%7B6%7D%20%5C%20%5C%20T%2Fs)
Explanation:
Given that
An isotropic point source emits light at a wavelength
= 500 nm
Power = 185 W
Radius = 380 m
Let's first calculate the The intensity of the wave , which is = ![\frac{Power }{Area}](https://tex.z-dn.net/?f=%5Cfrac%7BPower%20%7D%7BArea%7D)
= ![\frac{Power}{4 \pi r ^2}](https://tex.z-dn.net/?f=%5Cfrac%7BPower%7D%7B4%20%5Cpi%20r%20%5E2%7D)
= ![\frac{185 \ W}{ 4 \pi (380)^2}](https://tex.z-dn.net/?f=%5Cfrac%7B185%20%5C%20W%7D%7B%204%20%5Cpi%20%28380%29%5E2%7D)
= ![1.0195*10^{-4} \ W/m^2](https://tex.z-dn.net/?f=1.0195%2A10%5E%7B-4%7D%20%5C%20W%2Fm%5E2)
Now;
The amplitude of the magnetic field is calculated afterwards by using poynting vector
i.e
![I = (\frac{c}{2 \mu_0 })B_{max^2}](https://tex.z-dn.net/?f=I%20%3D%20%28%5Cfrac%7Bc%7D%7B2%20%5Cmu_0%20%7D%29B_%7Bmax%5E2%7D)
![B_{max^2} = (\frac{2 \mu_0 I}{ c})](https://tex.z-dn.net/?f=B_%7Bmax%5E2%7D%20%3D%20%20%28%5Cfrac%7B2%20%5Cmu_0%20%20%20I%7D%7B%20c%7D%29)
![B_{max^2} = (\frac{2 *4 \pi *10^{-7}*1.0195*10^{-4}}{ 3*10^8})](https://tex.z-dn.net/?f=B_%7Bmax%5E2%7D%20%3D%20%20%28%5Cfrac%7B2%20%2A4%20%5Cpi%20%2A10%5E%7B-7%7D%2A1.0195%2A10%5E%7B-4%7D%7D%7B%203%2A10%5E8%7D%29)
![B_{max^2} = 8.5409*10^{-19}](https://tex.z-dn.net/?f=B_%7Bmax%5E2%7D%20%3D%208.5409%2A10%5E%7B-19%7D)
![B_{max} = \sqrt {8.5409*10^{-19}}](https://tex.z-dn.net/?f=B_%7Bmax%7D%20%3D%20%5Csqrt%20%7B8.5409%2A10%5E%7B-19%7D%7D)
![B_{max} = 9.242*10^{-10}](https://tex.z-dn.net/?f=B_%7Bmax%7D%20%3D%209.242%2A10%5E%7B-10%7D)
The magnetic field wave equation can now be expressed as;
![B = B_{max} sin (kx - \omega t)](https://tex.z-dn.net/?f=B%20%3D%20B_%7Bmax%7D%20sin%20%28kx%20-%20%5Comega%20t%29)
Taking the differentiation
![\frac{dB}{dt}= - \omega B_{max} \ cos ( kx - \omega t)](https://tex.z-dn.net/?f=%5Cfrac%7BdB%7D%7Bdt%7D%3D%20-%20%5Comega%20B_%7Bmax%7D%20%5C%20cos%20%28%20kx%20-%20%5Comega%20t%29)
The maximum value ;
![\frac{dB}{dt} = \omega B _{max}](https://tex.z-dn.net/?f=%5Cfrac%7BdB%7D%7Bdt%7D%20%3D%20%5Comega%20B%20_%7Bmax%7D)
where ;
![\omega = 2 \pi f\\\omega = \frac{2 \pi c}{\lambda}](https://tex.z-dn.net/?f=%5Comega%20%3D%202%20%5Cpi%20f%5C%5C%5Comega%20%3D%20%5Cfrac%7B2%20%5Cpi%20c%7D%7B%5Clambda%7D)
then
![\frac{dB}{dt} = \frac{2 \pi c}{\lambda} B _{max}](https://tex.z-dn.net/?f=%5Cfrac%7BdB%7D%7Bdt%7D%20%3D%20%5Cfrac%7B2%20%5Cpi%20c%7D%7B%5Clambda%7D%20B%20_%7Bmax%7D)
![\frac{dB}{dt} = \frac{2 \pi 3*10^8*9.242*10^{-10}}{500*10^{-9}}](https://tex.z-dn.net/?f=%5Cfrac%7BdB%7D%7Bdt%7D%20%3D%20%5Cfrac%7B2%20%5Cpi%203%2A10%5E8%2A9.242%2A10%5E%7B-10%7D%7D%7B500%2A10%5E%7B-9%7D%7D)
![\frac{dB}{dt} = 3484751.917](https://tex.z-dn.net/?f=%5Cfrac%7BdB%7D%7Bdt%7D%20%3D%203484751.917)
![\frac{dB}{dt} = 3.49 *10^{6} \ \ T/s](https://tex.z-dn.net/?f=%5Cfrac%7BdB%7D%7Bdt%7D%20%3D%203.49%20%2A10%5E%7B6%7D%20%5C%20%5C%20T%2Fs)
Answer:
to find the slope you need to find the change in distance then you divide by the corresponding change in time
eg
( 4-2) ÷ (2-1)
= 2m/s