Answer:
-4.0 N
Explanation:
Since the force of friction is the only force acting on the box, according to Newton's second law its magnitude must be equal to the product between mass (m) and acceleration (a):
(1)
We can find the mass of the box from its weight: in fact, since the weight is W = 50.0 N, its mass will be

And we can fidn the acceleration by using the formula:

where
v = 0 is the final velocity
u = 1.75 m/s is the initial velocity
t = 2.25 s is the time the box needs to stop
Substituting, we find

(the acceleration is negative since it is opposite to the motion, so it is a deceleration)
Therefore, substituting into eq.(1) we find the force of friction:

Where the negative sign means the direction of the force is opposite to the motion of the box.
Answer:
No we cannot
Explanation:
But what causes a ring to appear around the moon? This phenomenon is called a "moon halo." According to the National Weather Service, this ring of light, which is actually an optical illusion, forms around the moon when moonlight refracts off ice crystals in cirrus clouds, high up in the Earth's atmosphere.
Answer:
Explanation:
1 ) Magnetic field due to a circular coil carrying current
= μ₀I / 2r
I is current , r is radius of the wire , μ₀ = 4π x 10⁻⁷
= 4π x 10⁻⁷ x 15 / (2 x 3.5 x 10⁻²)
= 26.9 x 10⁻⁵ T
2 )
Negative z direction .
The direction of magnetic field due to a circular coil having current is known
with the help of screw rule or right hand thumb rule.
3 )
If we decrease the radius the magnetic field will:__increase _____.
A. Increase.
Magnetic field due to a circular coil carrying current
B = μ₀I / 2 r
Here r is radius of the coil . If radius decreases magnetic field increases.
So magnetic field will increase.
When storm clouds produce lightening and thunder, then, potential energy changes into kinectic energy.
The clouds become negatively charged,and the ground is positively charged during a storm. So there creates a potential difference between the charged clouds and the ground. And when this becomes huge so much that it over comes the electrical insulation cover of air, the electrons jump to the ground.i.e. the potential energy changes into kinetic energy.