Before the driver applies the brakes ( with the reaction time ):
d 1 = v0 · t = 20 m/s · 0.53 s = 10.6 m
After that:
v = v0 - a · t1
0 = 20 m/s - 7 · t1
7 · t1 = 20
t1 = 2.86 s
d 2 = v 0 · t1 - a · t1² / 2
d 2 = 20 m/s · 2.86 s - 7 m/s² · (2.86 s)²/2 = 57.2 m - 28.6 m = 28.6 m
d = d 1 + d 2 = 10.6 m + 28.6 m = 39.2 m
Answer: the stopping distance of a car is 39.2 m.

5 0

2 years ago

Help! Please:) Amd Thank you!!!

Mrrafil [7]

They get 2/3 because 2 divided by 3=2/3.

8 0

3 years ago

3. A children's slide is 10 feet long and inclines 64° from the ground. The

Nata [24]

Answer:

87.0°

Step-by-step explanation:

The law of sines can be used to solve this. We have two sides of a triangle and the angle opposite one of them. We want to find the angle opposite the other known side.

In the attached, the triangle is ΔACS. We have side "a" = 9, and side "c" = 10. Angle A is given as 64°. The law of sines tells us ...

sin(C)/c = sin(A)/a

sin(C) = (c/a)sin(A)

C = arcsin((c/a)sin(A)) = arcsin(10/9·sin(64°)) ≈ 87.03°

The ladder makes an angle of about 87° with the ground.

3 0

2 years ago

2/3 divided by 1/4 in its simplest form

rewona [7]

Answer:

8/3

Step-by-step explanation:

to divide by a fraction multiply the reciprocal

2/3×4

calculate the product

2×4=8

8/3

5 0

3 years ago

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