A closely wound search coil has an area of , turns, and a resistance of . It is connected to a

If only an external force can change the velocity of a body, how can the internal force of the brakes bring a car to rest? 1. It

RoseWind [281]

Answer:

4. It is the force of the road on the tires (an external force) that stops the car.

Explanation:

If there is no friction between the road and the tires, the car won't stop.

You can see this, for example, when there is ice on the road. You can still apply the brakes (internal force), but since there is no friction (external force) the car won't stop.

The force of the brakes on the wheels is not what makes the car stop, it is the friction of the road against still tires that makes it stop.

3 0

3 years ago

I need help plz and thank you❤

anzhelika [568]

I think:
In motion- 40
Not moving- 20

6 0

2 years ago

The parallel plates in a capacitor, with a plate area of 7.90 cm2 and an air-filled separation of 2.70 mm, are charged by a 7.90

s2008m [1.1K]

Answer:

A) 26V

Explanation:

(a) the potential difference between the plates

Initial capacitance can be calculated using below expresion

C1= A ε0/ d1

Where d1= distance between = 2.70 mm= 2.70× 10^-3 m

ε0= permittivity of space= 8.85× 10^-12 Fm^-1

A= area of the plate = 7.90 cm2 = 7.90 ×10^-4 m^2

If we substitute the values we

C1= A ε0/ d1

=( 7.90 ×10^-4 × 8.85× 10^-12 )/2.70× 10^-3

C1=2.589 ×10^-12 F= 2.59 pF

Initial charge can be determined using below expresion

q1= C1 × V1

V1=2.589 ×10^-12 F

V1= voltage=7.90 V

If we substitute we have

q1= 2.589 ×10^-12 × 7.90

q1= 20.45×10^-12C

20.45 pC

Final capacitance can be calculated as

C2= A ε0/ d2

d2=8.80 mm= /8.80× 10^-3

7.90 ×10^-4 × 8.85× 10^-12 )/8.80× 10^-3

C1=0.794 ×10^-12 F= 0.794 pF

Final charge= initial charge

q2=q1 (since the battery is disconnected)

q2=q1= 20.45 pC

Final potential difference

V2= q/C2

= 20.45/0.794

= 26V

6 0

3 years ago

Which sentences describe the cyclone device?

Yakvenalex [24]

Answer:

✓ A cyclone device accumulates fine particulates from the air by making a dirty air stream flow in a spiral path inside a cylindrical chamber.

✘ It consists of several long and narrow fabric filter bags suspended upside-down in a large enclosure.

✓ When dirty air enters the chamber, the larger particulates strike the chamber wall and fall into a conical dust hopper at the bottom.

✘ Fans blow dirt-filled air upward from the bottom of the enclosure, trapping dirt particles inside the filter bags and releasing clean air from the top.

✓ The top of the chamber has an outlet that lets out cleaned air.

Basically, any of these choices that have the word "filter" are wrong. The point of the cyclone device is to separate the particles without the use of filters. You can tell the right answers based on the picture attached below.