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Rzqust [24]
3 years ago
12

A driver is moving at 17.0 m/s when she sees a child on a bike 65m ahead of her. If the car can brake at 4.9 m/s^2 and the drive

rs reaction time is 1.6 s, can she avoid hitting the child
Physics
1 answer:
Lera25 [3.4K]3 years ago
7 0

Answer:

The driver can  avoid the child because at the time she brake 1.6s the car just move 20.928 meters so is far to the 65 meters where the kind is

Distance= 20.928 m

Explanation:

V_{o} = 17 \frac{m}{s} \\a= -4.9 \frac{m}{s^{2} }\\ t= 1.6 s

Distance the kid is 65m so the car have to be less in the time she is braking

So to calculated the distance while she is braking

X_{f} = X_{o} +V_{o}*t + \frac{1}{2} * a *t^{2}\\ X_{f} = 0m +17 \frac{m}{s} *1.6 s + \frac{1}{2} * 4.9 \frac{m}{s^{2} } *(1.6s)^{2}\\X_{f} = 27.2 m+ (-6.272 m)\\X_{f} = 20.928 m

The distance of the car is less than the distance of the kid in his bike

So she didn't hit him

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John is going to use a rope to pull his sister Laura across the ground in a sled through the snow. He is pulling horizontally wi
bulgar [2K]

Answer:

The mass of Laura and the sled combined is 887.5 kg

Explanation:

The total force due to weight of Laura and friction on the sled can be calculated as follows;

F_T = F_L+F_S

     = (400 + 310) N

     = 710 N

From Newton's second law of motion, "the rate of change of momentum is directly proportional to the applied force.

F_T = \frac{(M_L+M_S)V}{t}

where;

M_L is mass of Laura and

M_S is mass of sled

Mass of Laura and the sled combined is calculated as follows;

(M_L+M_S) = \frac{F_T*t}{V}

given

V = Δv = 4-0 = 4m/s

t = 5 s

(M_L+M_S) = \frac{710*5}{4}\\\\(M_L+M_S) =  887.5 kg

Therefore, the mass of Laura and the sled combined is 887.5 kg

4 0
3 years ago
Which statement is true?
vivado [14]

Answer:

The speed of sound in air is not affected by the temperature

Explanation:

It just isn't™

4 0
3 years ago
A sample with a path length of 1 cm absorbs 99.0% of the incident light at a wavelength of 274 nm, measured with respect to an a
Ksju [112]

Answer:

17. NADH has a molar extinction coefficient of 6200 M2 cm at 340 nm. Calculate the molar concentration of NADH required to obtain an absorbance of 0.1 at 340 nm in a 1-cm path length cuvette. 18. A sample with a path length of 1 cm absorbs 99.0% of the incident light at a wavelength of 274 nm, measured with respect to an appropriate solvent blank. Tyrosine is known to be the only chromophore present in the sample that has significant absorption at 274 nm. Calculate the molar concentration of tyrosine in the sample.

Explanation:

8 0
3 years ago
Find the average velocity of the car during the time last three second interval. Answer in units of m/s.
Pani-rosa [81]

Answer:

<u>Average Velocity:</u>

When a body covers some displacement moving from point A to B, in a given time,t. Then dividing the total distance covered by the time taken to complete the displacement is called as the average velocity of that car.

We can calculate the average velocity of car by subtracting the initial displacement of a body,s₁ from  the final displacement position of the body, s₂. And then dividing by the initial time,t₁ been subtracted from the final time,t₂.

  • Δv=x₂-x₁/t₂-t₁,

We will get the required results, now if we want to obtain the results in the final three seconds then, we can have the following explanation to that as given.

Explanation:

Lets say, that we have the car moving for 10 seconds and then it stops at the eleventh second of the trip on final position, of the displacement. Then we divide the whole trips into small segments, as we will have the different velocity at each interval but, the velocity is unknown at the last 3 seconds is unknown=?.  

  • Total time taken, Δt= 11 seconds,
  • Then lets say the velocity at the 8th second is , v=25 m/s,then
  • Δv=x₂-(25)/11-0,⇒Δv=x₂-25/11,
3 0
3 years ago
How is wavelength related to a waves energy?
andreyandreev [35.5K]

Answer:

The energy of a wave is directly proportional to its frequency, but inversely proportional to its wavelength. In other words, the greater the energy, the larger the frequency and the shorter (smaller) the wavelength.

Explanation:

i hope it will help u buddy✅

8 0
3 years ago
Read 2 more answers
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