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3 years ago

10

a motorist traveling at 18m/s approaches traffic lights when he is 30 m from the stop line they turn red it takes 0.7 s before h

e can react by applying the brakes

1 answer:

Gelneren [198K]3 years ago

7 0

Answer:

35.2m

Explanation:

S= V^2 - U^2 ÷ 2A

S= (0) - (18) ÷ 2(4.6)

S= 324 ÷ 92

S= 35.2m

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A 720 g softball is traveling at 15.0 m/s when caught. If the force of the glove on the ball is 520 N, what is the time it takes

Sholpan [36]

Answer:

The time it takes the ball to stop is 0.021 s.

Explanation:

Given;

mass of the softball, m = 720 g = 0.72 kg

velocity of the ball, v = 15.0 m/s

applied force, F = 520 N

Apply Newton's second law of motion, to determine the time it takes the ball to stop;

$F = ma = \frac{mv}{t} \\\\t = \frac{mv}{F} \\\\t = \frac{0.72 \ \times \ 15}{520} \\\\t = 0.021 \ s \\$

Therefore, the time it takes the ball to stop is 0.021 s.

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Explanation:

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4 years ago

Read 2 more answers

In 8.4 s a fisherman winds 2.9 m of fishing line onto a reel whose radius is 3.0 cm (assumed to be constant as an approximation)

alukav5142 [94]

Answer:

The angular speed of the reel is 11.33 rad/s

Explanation:

Given

The fisherman takes t = 8.4 s to wind distance x = 2.9 m into a circle radius of r = 3 cm = 0.03 m

Than the tangencial speed equals the change in the distance to the time

v = $\frac{x}{t}$ = $\frac{2.9 m}{8.4 s} = 0.34 \frac{m}{s}$

Knowing the tangencial velocity is proportional to the radius r and the angular velocity

v = r*w

w = $\frac{0.34 m/s}{0.03 m} = 11.33 \frac{rad}{s}$

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4 years ago