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Lady_Fox [76]
3 years ago
9

Driving at 75m/s, you hit the brakes on your new car, accelerating at a rate of -20m/s. How long will it take the car to come to

rest?
Physics
1 answer:
soldi70 [24.7K]3 years ago
5 0

Answer:

3.75s

Explanation:

Using equation of motion, t= (v-u)/a

where v=0, u=75 and a=-20

t=-75/-20=75/20=3 /.75

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An electric bulb is marked 40volts ,230w another bulb is marked 40w,110v
Andrej [43]

Answer:

a. The ratio of their resistance is 2783:64

b. The ratio of their energy is 4:23

c. The charge on the first bulb is 5.75 C

The charge on the second bulb is 0.\overline {36} C

Explanation:

The voltage on one of the electric bulbs, V₁ = 40  volts

The power rating of the bulb, P₁ = 230 w

The voltage on the other electric bulbs, V₂ = 110 volts

The power rating of the bulb, P₂ = 40 w

a. The power is given by the formula, P = I·V = V²/R

Therefore, R = V²/P

For the first bulb, the resistance, R₁ = 40²/230 ≈ 6.96

The resistance of the second bulb, R₂ = 110²/40

The ratio of their resistance, R₂/R₁ = (110²/40)/(40²/230) = 2783/64

∴ The ratio of their resistance, R₂:R₁ = 2783:64

b. The energy of a bulb, E = t × P

Where;

t = The time in which the bulb is powered on

∴ The energy of the first bulb, E₁ = 230 w × t

The energy of the second bulb, E₂ = 40 w × t

The ratio of their energy, E₂/E₁ = (40 w × t)/(230 w × t) = 4/23

∴ The ratio of their energy, E₂:E₁ = 4:23

c. The charge on a bulb, 'Q', is given by the formula, Q = I × t

Where;

I = The current flowing through the bulb

From P = I·V, we get;

I = P/V

For the first bulb, the current, I = 230 w/40 V = 5.75 amperes

The charge on the first bulb per second (t = 1) is therefore;

Q₁ = 5.75 A × 1 s = 5.75 C

The charge on the first bulb, Q₁ = 5.75 C

Similarly, the charge on the second bulb, Q₂ = (40 W/110 V) × 1 s = 0.\overline {36} C

The charge on the second bulb, Q₂ = 0.\overline {36} C.

d. The question has left out parts

4 0
3 years ago
what would happen when an inflated balloon is place in an ice bath and the atmosphere pressure has not changed?
ruslelena [56]

The inflated balloon shrinks when it is placed in an ice bath with no change in atmospheric pressure.  

<u>Explanation:</u>

        When the inflated balloon is subjected to an ice bath, it shrinks. This is due to the fact that smaller volume gets occupied by the air/gas inside the balloon as the temperature decreases. Hence, causes the balloon walls to collapse.  

         An ice bath also lowers the overall air temperature of the balloon inside. As the temperature decreases, the air molecules move more slowly and with lower energy. Because of the particle's lower energy, their collisions with the walls are not enough to keep the inflated balloon.

7 0
3 years ago
A car moves at 20 m s' for 15 minutes. Calculate the distance travelled
Firdavs [7]

Explanation:

Calculating this according to the m/s rate

Now solving the question

If the car goes 20 m/s mathematically we can generate it as

15 × 60 = 600 secs

If the car goes 20 meters per every second it means

The car will go 20 meters for 900 secs

Which is 900 ×20 = 18000m/s

=18000÷1000 = 1km

Therefore the answer is 18km

6 0
3 years ago
At what distance along the central perpendicular axis of a uniformly charged plastic disk of radius 0.390 m is the magnitude of
aliina [53]
<span>Radius, the distance from the centre = 0.390
 Electric field is equal to half of the magnitude. E2 = E / 2
 Given
E1 = E2 E1 = k x Q / r^2
  E2 = (k x Q / r2^2) / 2
  Equating the both we get 2 x r^2 = r2^2
 r2 = square root of (2 x r1^2) = square root of (2) x r = 1.414 x 0.390
  r2 = 1.414 x 0.390 = 0.551 m</span>
3 0
3 years ago
A 6.2 kg cannonball is fires from a 280 kg cannon. The cannon recoils with a velocity of 4.9 m/s. What is the velocity of the ca
lara [203]

Answer:

666 bc its on its way to my house

Explanation:

3 0
3 years ago
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