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Alchen [17]
3 years ago
15

A car skids to a stop, leaving four skid marks with an average length of 60 feet. The road is asphalt. Skid tests reveal a drag

factor of 0.75. Since all four wheels were braking, the braking efficiency is 100% or 1.00. To the nearest mile per hour, what was the car’s speed at the time of the accident.
Mathematics
1 answer:
SSSSS [86.1K]3 years ago
5 0

Answer:

37 mph

Step-by-step explanation:

Sum of forces on the car in the y direction:

∑F = ma

N − mg = 0

N = mg

Sum of forces on the car in the x direction:

∑F = ma

-Nμ = ma

-mgμ = ma

-gμ = a

Given μ = 0.75 and g = 32 ft/s²:

a = -(32 ft/s²) (0.75)

a = -24 ft/s²

Use kinematics to find the initial velocity.

v² = v₀² + 2aΔx

(0 ft/s)² = v₀² + 2 (-24 ft/s²) (60 ft)

v₀ ≈ 53.7 ft/s

v₀ ≈ 37 mph

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8. Sven sells hamburgers at a ballpark. He earns $14.50/h, plus $0.50
Komok [63]

Answer:

Part A: $55.50

Part B: 52 hamburgers(sorry if I am wrong for part b but I think it is right)

Step-by-step explanation:

Part A:     $14.50 x 3= $43.50  +         24 x $0.50= $12=        

 ($ earned per hrs  x hrs worked)+  ($ per hamburger sold x times amount)

Hence $43.50 + $12= $55.50.

Part B:        $14.50 x 6.5 = $94.25                           $120 - $94.25= $25.75

 ($ earned per hrs  x hrs worked x x hrs worked)   ($ earned - $ earn from shif

 $25.75/0.50=51.5 (51.5 rounded to nearest burgers is 52 burgers)

Hence answer is 52 burgers.

Please rate Good and mark Brainliest

Thank You

5 0
3 years ago
libon's new car can travel 45 miles on 1 gallon of of gas. at this rate how far can the car travel on 7 gallons
Setler [38]

Answer:

315

Step-by-step explanation:

If one gallon of gas can give you 45 miles, than multiple 45 ( the miles ) times 7 (the gallons of gas) and you will have your answer :)

4 0
2 years ago
What to numbers can go into 72 and 45
ratelena [41]

Answer:

3 and 9

Step-by-step explanation:

3 * 24 = 72

9 * 8 = 72

3 * 15 = 45

9 * 5 = 45

8 0
3 years ago
Read 2 more answers
A manufacturer is planning to sell a new product at the price of 210 dollars per unit and estimates that if x thousand dollars i
sattari [20]

Answer:

Development costs: $2757

Promotion costs: $3155

Step-by-step explanation:

This might seem like a two-variable problem, but in actuality it's not - because the demand function is a sum of two components, each being independent and using only one variable, we can solve for the two separately.

Moreover, the price per unit and cost per unit is constant, so each product yields exactly $80 ($210 - $130).

Let's solve separately.

We need to maximize:

$80 * 160y/(y+4) - 1000y = $12800 * y/(y+4) - $1000*y

$80 * 170x/(x+7) - 1000x = $13600 * x/(x+7) - $1000*x

Let's go:

$12800 * y/(y+4) - $1000*y = $12800 * (1 - 4/(y+4)) - $1000y = $12800 - $51200/(y+4) - $1000*y

we analyze the derivative. $12800 is a constant, so we can skip it. Derivative of 1/(y+4) is -(y+4)^-2, derivative of $1000y is $1000.

deriv = $51200/(y+4)/(y+4) - $1000

We find the changepoints by analyzing $51200/(y+4)/(y+4) - $1000 = $0. We don't need to worry about y+4 = 0 because we cannot spend negative money on development/advertisement.

(y+4)^2 = $51.2

y+4 ~= 7.155417528 (or -y-4 = 7.1554... but it doesn't make sense because negative budget so we don't analyze).

y ~= 3.155417528

lastly, we should check that it's actually a maximum there - but it is, the original function goes to negative infinity.

rounding $1000y to the nearest dollar gives us $3155

Let's do the same for x:

$13600 * x/(x+7) - $1000*x = $13600 * (1 - 7/(x+7)) - $1000x = $13600 - $95200/(x+7) - $1000*x

deriv = $95200/(x+7)/(x+7) - $1000

$95200/(x+7)/(x+7) - $1000 = $0

(x+7)^2 = 95.2

(x+7) ~= 9.75704873412

x ~= 2.75704...

rounding $1000x to the nearest dollar yields $2757

3 0
3 years ago
SPIRAL REVIEW - Find the value of the expression below.<br><br> 96 ÷ 4² + (25×2) - 15 - 3
Lunna [17]

Answer:

38

Step-by-step explanation:

96/16  

+(25)(2)−15−3

=6+(25)(2)−15−3

=6+50−15−3

=56−15−3

=41−3

=38

3 0
3 years ago
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