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marta [7]
3 years ago
13

The driver of a car traveling 110 km/h slams on the brakes so that the car undergoes a constant acceleration, skidding to a comp

lete stop in 4.5 sec. What is the average acceleration of the car during braking?
Physics
1 answer:
Ber [7]3 years ago
5 0

Answer: -6.80\ ms^{-2}

Explanation:

We know that the formula for acceleration is given by:

a=\dfrac{v-u}{t} , where v = Final velocity

u= Initial velocity

Given :  The driver of a car traveling 110 km/h slams on the brakes so that the car undergoes a constant acceleration.

i.e. u=   110 km/h =\dfrac{110\times1000}{3600}\approx35.6\ m/s  [∵  1 km= 100 meters and 1 hour = 3600 seconds]

v=  0  m/s ( At brake , final velocity becomes 0)

t=4.5 seconds  

Substitute all the values in the formula , we get

a=\dfrac{0-30.56}{4.5}\approx-6.80\ ms^{-2}

Hence, the average acceleration of the car during braking is -6.80\ ms^{-2}.

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4. Bobby places a firecracker in plastic monster truck . The firecracker explodes sending a 0.75 kg piece of the car forward at
emmainna [20.7K]

Answer:

m₂ = 1.2 [kg]

Explanation:

Since the explosion causes a force in a certain instant of time, for both bodies there is an equal impulse. In such a way that we can relate both impulses to be able to find the mass of the body needed in the next equation.

m_{1}*v_{1}=m_{2}*v_{2}

where:

m₁ = mass of the first piece = 0.75 [kg]

v₁ = velocity of the first piece = 7.2 [m/s]

m₂ = mass of the second piece [kg]

v₂ = velocity of the second piece = 4.5 [m/s]

0.75*7.2=m_{2}*4.5\\m_{2}=1.2[kg]

4 0
3 years ago
In dragons, the allele B produces blue body color. The allele b produces green body color. The B allele is dominant to the b all
Ierofanga [76]

Answer:

bb

Explanation:

Allele B codes for blue colour.

Allele b codes for green colour.

A gene is usually denoted by two alleles and allele B is dominant over allele b. This means that when B and b are together as Bb, blue colouration will be expressed while green colouration will be repressed.

Hence, for the green colouration to be expressed, B must not be present. <em>The genotype therefore must be bb.</em>

3 0
3 years ago
A ball of mass 0.190 kg has a velocity of 1.50 i m/s; a ball of mass 0.305 kg has a velocity of -0.401 i m/s.They meet in a head
Mice21 [21]

Answer:

<h3>0.329m/s</h3>

Explanation:

According to law of conservation of momentum, the momentum of the object before collision is equal to that of the object after collision. Using the formula

m1u1 + m2u2 = (m1+m2)v

m1 and m2 are the masses of the object

u1 and u2 are the respective initial velocities

v is the final velocity

Given

m1 = 0.190kg

u1 = 1.5m/s

m2 = 0.305kg

u2 = -0.401m/s

Substitute

0.19(1.5)+(0.305)(-0.401) = (0.19+0.305)v

0.285 - 0.122305 = 0.495v

0.162695 = 0.495v

v = 0.162695 /0.495

v = 0.329m/s

<em>Hence their velocities after collision is 0.329m/s in the positive x direction</em>

<em></em>

8 0
3 years ago
A "gauge 8" jumper cable has a diameter d of 0.326 centimeters. The cable carries a current I of 30.0 amperes. The electric fiel
AveGali [126]

Answer:

0.0979 N/c

Explanation:

Electric field, E is given as a product of resistivity and current density

E=jP where P is resistivity and j is current density

But the current density is given as

j=\frac {I}{A} where I is current and A is area and A=\pi r^{2}

Substituting this into the first equation then E=P\times \frac {I}{\pi r^{2}}

Given diameter of 0.259 cm= 0.00259 m and the radius will be half of it which is 0.001295 m

E=1.72\times 10^{-8}\times \frac {30}{\pi \times 0.001295^{2}}=9.79\times 10^{-2} N/c=0.0979 N/c

4 0
3 years ago
8
Dovator [93]

Answer:

25 atoms

Explanation:

7 0
3 years ago
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