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liraira [26]
3 years ago
8

The driver of a 2.0 × 10³ kg red car traveling on the highway at 45m/s slams on his brakes to avoid striking a second yellow car

in front of him, which had come to of because locking ahead.After the brakes are applied a constant friction force of 7.5 × 10³ N acts on the car ignore air resistance.
a₎ Determine the least distance should the brakes be applied to avoid a collision with the other vehicle?
Physics
1 answer:
nignag [31]3 years ago
6 0

Answer:

Explanation:

a = F/m = 7500/2000 = 3.75 m/s²

v² = u² + 2as

s = (v² - u²) / 2a

s = (0² - 45²) / (2(-3.75))

s = 270 m

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the planet neptune is approximately 4.5*10^9 kilometers from the sun. The planet Venus is approximately 1.1*10^8 kilometers from
Firlakuza [10]

Answer:

Neptune is approximately 41 times as far from the sun as Venus

Explanation:

Estimate = distance of Neptune from the sun ÷ distance of Venus from the sun = 4.5×10^9 ÷ 1.18×10^8 = 40.9 (approximately 41)

7 0
4 years ago
Calculate the magnitude of the maximum orbital angular momentum Lmax for an electron in a hydrogen atom for states with a princi
erica [24]

Answer:

L_max= 0

Explanation:

The formula for magnitude of maximum orbital angular momentum is given by

L_{max}= \sqrt{l(l+1)\bar{h}}

l= orbital quantum number

l= n-1

n= shell number or principal quantum number

for n=1 , l=0

therefore, L_{max}= \sqrt{0(0+1)\bar{h}}

L_max= 0

3 0
4 years ago
I would love to stretch a wire from our house to the Shop so I can 'call' my husband in for meals. The wire could be tightened t
Semenov [28]
Note: I'm not sure what do you mean by "weight 0.05 kg/L". I assume it means the mass per unit of length, so it should be "0.05 kg/m".

Solution:
The fundamental frequency in a standing wave is given by
f= \frac{1}{2L} \sqrt{ \frac{T}{m/L} }
where L is the length of the string, T the tension and m its mass. If  we plug the data of the problem into the equation, we find
f= \frac{1}{2 \cdot 24 m} \sqrt{ \frac{240 N}{0.05 kg/m} }=1.44 Hz

The wavelength of the standing wave is instead twice the length of the string:
\lambda=2 L= 2 \cdot 24 m=48 m

So the speed of the wave is
v=\lambda f = (48 m)(1.44 Hz)=69.1 m/s

And the time the pulse takes to reach the shop is the distance covered divided by the speed:
t= \frac{L}{v}= \frac{24 m}{69.1 m/s}=0.35 s
3 0
3 years ago
9. The Metro Rail makes a stop at NRG Stadium to pick up some Texans fans after the game. After
attashe74 [19]

Answer:

It takes the train 7.5 seconds to reach top speed

The train travels 112.5 meters before it reaches its top speed

Explanation:

The Metro Rail makes a stop at NRG Stadium to pick up some Texans

fans after the game

After  all the passengers board, the train accelerates at a rate of 4 m/s²

to a top speed of 30 m/s

We need to find the train takes how many seconds to reach the

top speed

Given is:

→ The train start from rest, then its initial speed u = 0

→ It acceleration a = 4 m/s²

→ Its top speed v = 30 m/s

To find the time we can use this rule;

→ t=\frac{v-u}{a}

→ t=\frac{30-0}{4}=\frac{30}{4}=7.5 seconds

<em>It takes the train 7.5 seconds to reach top speed</em>

<em></em>

Now we need to find how far the train travels before reaches top speed

We can use this rule;

→ v² = u² + 2as, where s is the distance

→ v = 30 m/s , u = 0 , a = 4 m/s²

Substitute these values in the rule

→ (30)² = 0 + 2(4) s

→ 900 = 8 s

Divide both sides by 8

→ s = 112.5 m

<em>The train travels 112.5 meters before it reaches its top speed </em>

7 0
3 years ago
A horizontal force of magnitude 46.3 n pushes a block of mass 4.14 kg across a floor where the coefficient of kinetic friction i
IrinaVladis [17]
A) Calling F the intensity of the horizontal force and d the displacement of the block across the floor, the work done by the horizontal force is equal to
W=Fd = (46.3 N)(4.25 m)=196.8 J

b) The work done by the frictional force against the motion of the block is equal to:
W_f =  -F_f d =- (\mu mg) d =-(0.609)(4.14 kg)(9.81 m/s^2)(4.25 m)=
=-105.1 J
Part of these 105.1 Joules of work becomes increase of thermal energy of the block (\Delta E_B), and part of it becomes increase of thermal energy of the floor (\Delta E_F). We already know the increase in thermal energy of the block (38.2 J), so we can find the increase in thermal energy of the floor:
\Delta E_F = 105.1 J - \Delta E_B = 105.1 J-38.2 J=66.9 J

c) The net work done on the block is the work done by the horizontal force F minus the work done by the frictional force (the frictional force acts against the motion, so we must take it with a negative sign):
W_{net}=W-W_f=196.8 J-105.1 J=91.7 J
For the work-energy theorem, the work done on the block is equal to its increase of kinetic energy:
W_{net} = \Delta K
So, we have \Delta K=+91.7 J


5 0
3 years ago
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