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3 years ago

A car slows down from 80 km/h to 60 km/h in 2 seconds.

Physics

1 answer:

Andreyy893 years ago

6 0

Answer:

please mark brainlist

Explanation:

Initial speed u=80 km/h=80×185=22.22 m/s

Final speed v=60 km/h=60×185=16.67 m/s

Using v=u+at

Or 16.67=22.22+α×5

⟹ a=−1.1 m/s2

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What is the magnitude of the torque that the axle must apply to prevent the disk from rotating?

mihalych1998 [28]

The required torque at the axle, is given by the difference between the

moments of the applied forces.

The torque required is 19.62 N·m counterclockwise

Reasons:

The given parameters are;

Mass of the disk, m = 5.0 kg

Location of the axle = Half the radius of the disk

Diameter of the disk, D = 40 cm = 0.4 m

Applied mass, 0.1 m from the axle = 15 kg

Applied mass, 0.3 m from the axle = 10 kg

Required:

Magnitude of torque at the axle that prevent the disk from rotating

Solution:

Torque needed = Clockwise moment - Counterclockwise moment

Clockwise moment = (10 kg × 0.3 m + 5 kg × 0.1 m) × 9.81 m/s² = 34.335 N·m

Counterclockwise moment = 15 kg × 0.1 m × 9.81 m/s² = 14.715 N·m

τ + Counterclockwise moment = Clockwise moment

τ + 14.715 N·m = 34.335 N·m

Torque required, τ = 34.335 N·m - 14.715 N·m = 19.62 N·m

Torque required, τ = 19.62 N·m counterclockwise

Learn more here:

brainly.com/question/19044661

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The probable question drawing obtained from a similar question online is attached

7 0

2 years ago

A 3.00N rock is thrown vertically into the air from the ground. At h=15.0m, v=25m/s upward. Use the work-energy theorem to find

butalik [34]

Answer:

so initial speed of the rock is 30.32 m/s

correct answer is b. 30.3 m/s

Explanation:

given data

h = 15.0m

v = 25m/s

weight of the rock m = 3.00N

solution

we use here work-energy theorem that is express as here

work = change in the kinetic energy ..............................1

so it can be written as

work = force × distance ...................2

and

KE is express as

K.E = 0.5 × m × v²

and it can be written as

F × d = 0.5 × m × (vf)² - (vi)² ......................3

here

m is mass and vi and vf is initial and final velocity

F = mg = m (-9.8) , d = 15 m and v{f} = 25 m/s

so put value in equation 3 we get

m (-9.8) × 15 = 0.5 × m × (25)² - (vi)²

solve it we get

(vi)² = 919

vi = 30.32 m/s

so initial speed of the rock is 30.32 m/s

5 0

3 years ago

During a blackout, you are trapped in a tall building. you want to call rescuers on your cell phone, but you can't remember whic

Gennadij [26K]

Let the height where we are trapped is H

now to find the time to reach the key at the bottom is given as

$y = v_i t + \frac{1}{2}at^2$

now we have

$H = \frac{1}{2}gt^2$

$t = \sqrt{\frac{2H}{g}}$

now if the speed of sound is considered to be 340 m/s then time taken by the sound to reach at the top is given as

$t = \frac{H}{340}$

now the total time is given as

$\sqrt{\frac{2H}{g}} + \frac{H}{340} = 3.27$

now by solving above equation we have

H = 48 m

now height of one floor is 3 m

so our position must be

$N = \frac{48}{3} = 16 th \:floor$

3 0

3 years ago