Which of the vectors in the graph below is the negative of the vector v?

Which law is used to find the magnitude of a magnetic force?

Talja [164]

Answer:

The Flemings left hand rule is used to find the magnitude of a magnetic force

Explanation:

Fleming's left hand rule states that if the first three fingers are held mutually at right angles to one another, then the fore finger points into the direction of magnetic field the middle finger in the direction of current while the thumb points in the direction of force.

Mathematically

Magnetic Force F= BILsinθ

Where

B= magnetic field density Tesla

I= current

L= length of conductor

θ= angle of conductor with field

3 0

2 years ago

Suppose a 48-N sled is resting on packed snow. The coefficient of kinetic friction is 0.10. If a person weighing 660 N sits on t

Annette [7]

Assume the snow is uniform, and horizontal.

Given:

coefficient of kinetic friction = 0.10 = muK

weight of sled = 48 N

weight of rider = 660 N

normal force on of sled with rider = 48+660 N = 708 N = N

Force required to maintain a uniform speed

= coefficient of kinetic friction * normal force

= muK * N

= 0.10 * 708 N

=70.8 N

Note: it takes more than 70.8 N to start the sled in motion, because static friction is in general greater than kinetic friction.

8 0

2 years ago

A disk of mass M and radius R rotates at angular velocity ω0. Another disk of mass M and radius r is dropped on top of the rotat

AleksandrR [38]

Answer:

$\omega = \frac{(R^2\omega_o}{(R^2 + r^2)}$

Explanation:

As we know that there is no external torque on the system of two disc

then the angular momentum of the system will remains conserved

So we will have

$L_i = L_f$

now we have

$L_i = (\frac{1}{2}MR^2)\omega_o$

also we have

$L_f = (\frac{1}{2}MR^2 + \frac{1}{2}Mr^2)\omega$

now from above equation we have

$(\frac{1}{2}MR^2)\omega_o = (\frac{1}{2}MR^2 + \frac{1}{2}Mr^2)\omega$

now we have

$\omega = \frac{MR^2\omega_o}{(MR^2 + Mr^2)}$

$\omega = \frac{(R^2\omega_o}{(R^2 + r^2)}$

6 0

3 years ago

Snell's Law: Light traveling through water comes to a glass surface at an angle of incidence of

Lerok [7]

Answer:

1. The best definition of refraction is ____.

a. passing through a boundary

b. bouncing off a boundary

c. changing speed at a boundary

d. changing direction when crossing a boundary

Answer: D

Bouncing off a boundary (choice b) is reflection. Refraction involves passing through a boundary (choice a) and changing speed (choice c); however, a light ray can exhibit both of these behaviors without undergoing refraction (for instance, if it approaches the boundary along the normal). Refraction of light must involve a change in direction; the path must be altered at the boundary.

6 0

2 years ago

A ball is dropped from some height. It bounces off the floor and rebounds with a speed that is one-half the speed it had just be

Arada [10]

Answer:

The correct option is C

Explanation:

According to third equation of motion, v

2

=u

2

+2ax

Here, u=0 m/s

a=−g and x=−h

Negative sign indicates downward direction. Displacement and acceleration both are downwards.

So,v=±

2(−g)(−h)

We take minus sign because it is downwards.

v=−

2gh

After bouncing. velocity becomes 80% of v, i.e.,

v

′

=+0.8

2gh

(positive sign because the direction of ball has reversed after bouncing and is upwards.

Applying third equation of motion again, for u=v

′

, v=0 and a=−g

v

2

=u

2

+2×a×x

Thus,

0=0.64(2gh)+2(−g)x

or

x=0.64h

3 0

2 years ago