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Xelga [282]
3 years ago
13

A traffic accident detective measures the skid marks left by a car, 825kg. He determines that the distance between the point tha

t the driver slammed on the brakes and the point where the car came to a stop was 34.0 m. From a reference manual he determines that the coefficient of kinetic friction between the tires and the road under the prevailing conditions was 0.300. How fast was the car going when the driver applied the brakes? (This car was not equipped with anti-lock brakes.
Physics
1 answer:
deff fn [24]3 years ago
7 0
Doing a force balance on the car:
ma = Fr
ma = μmg
a = μg
a = 0.3(9.81)
a = 29.43 m/s2

Using the formula:
2ax = v2
2(29.43)(34) = v2
v = 44.74 m/s = 161.05 km/h

The car was going 44.74 m/s or 161.05 kph when the brakes were applied.
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A glider with mass m = 0.230 kg sits on a frictionless horizontal air track, connected to a spring with force constant k = 4.50
loris [4]

Answer

given,

mass of glider = 0.23 Kg

spring constant = k = 4.50 N/m

spring stretched to 0.130 m

The springs potential energy =

 U = \dfrac{1}{2}kx^2

 U = \dfrac{1}{2}\times 4.5 \times 0.13^2

        U = 0.038 J

at x = 0,the only energy will be kinetic .

 \dfrac{1}{2}mv^2=0.038

 \dfrac{1}{2}\times 0.23 \times v^2=0.038

         v² = 0.3304

         v = 0.575 m/s

displacement of the glider

      using conservation of energy

 \dfrac{1}{2}mv^2=\dfrac{1}{2}kx^2

 x =v\sqrt{\dfrac{m}{k}}

 x =3\times \sqrt{\dfrac{0.23}{4.5}}

        x = 0.678 m

8 0
3 years ago
Convert 27,549 into scientific notation
dezoksy [38]
2.7549 x 10^4 is the answer I hope this helped u
7 0
3 years ago
Fiberglass, an insulator, can be found in the wals and roofs of some houses and buildings. Why would an insulator be needed insi
GREYUIT [131]

It keeps the heat inside of the building

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3 years ago
Read 2 more answers
1. Is there a relationship between the volume of water displaced and the total volume of the block that has anything to do with
strojnjashka [21]

Answer:

The volume of the block is equal to the volume of water displaced by the block.

Explanation:

Volume refers to the amount of space occupied by a given object (in this case the block). When an object such as the block is immersed in water, it displaces its own volume of water. This volume of water displaced is equal to the volume of the block. Hence we can write;

Final Volume of water - Initial Volume of water= Water Displaced = Volume of the block

Recall that the density of a body is given by;

Density= mass/volume

If we obtain the volume of the block by measuring the volume of water displaced by the block, then we weigh the block using a weighing balance, we can obtain the density of the block easily from the relationship shown above.

8 0
3 years ago
Yashoda prepares some lime juice on a hot day. She adds 80 g of ice at a temperature of 0°C to 0.32 kg of lime juice. The temper
Vikentia [17]

Answer:

Explanation:

a )

hear energy required to melt 1 g of ice = 340 J ,

hear energy required to melt 80 g of ice = 340 x 80  J = 27220 J .

b ) energy gained by the melted ice ( water at O°C ) = m ct

where m is mass of water , s is specific heat and t is rise in temperature

= 80 x 4.2 x ( 8°C - 0°C)

= 2688 J .

c )

energy lost by lime juice = energy gained by ice and water

= 27220 J + 2688 J .

= 29908 J .

d )

Let specific heat required be S

Heat lost by lime juice = M S T

M is mass of lime juice , S is specific heat , T is decrease in temperature

= 320 g x S x ( 29 - 8 )°C

= 6720 S

For equilibrium

Heat lost = heat gained

6720 S = 29908 J

S = 4.45 J /g °C .

4 0
3 years ago
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