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Sladkaya [172]
2 years ago
12

A vehicle is moving at a speed of 20m/s suddenly the driver sees a fallen tree on the road, he instantly applies the brakes that

subject the car to a deceleration of -2m/s².Find
a) Time required by the car to stop.
b) distance covered before stopping.
Physics
1 answer:
NeTakaya2 years ago
6 0

Answer:

b) Distance covered before stopping.

Explanation:

If you want to find the distance d required to come to a stop starting at some initial speed v, with braking acceleration a, use the kinematic relation  

vf2 - vi2 = 2ad

vi = initial speed at the moment braking begins = v

vf = final speed = 0 (comes to a full stop)

-v2 = 2ad

d = -v2/(2a)

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the answer is the second one

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If X And Y two vectors have same magnitude, if X^Y=2 and X.Y =4 so, the angle between them ?​
devlian [24]

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An empty parallel plate capacitor is connected between the terminals of a 4.4-V battery and charged up. The capacitor is then di
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d

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3 years ago
An electric fan is turned off, and its angular velocity decreases uniformly from 500 rev/min to 200 rev/min in 4.00 s.
Veseljchak [2.6K]

Answer:

a) -1.25 rev/s² and 23.3 rev

b)  2.67s

Explanation:

a) ωФ_o_z = (500 rev/min)(1min/ 60s) => 8.333 rev/s

ωФ_Z= (200 rev/min)(1min/ 60s) => 3.333rev/s

time 't'= 4 s

angular acceleration 'αФ_Z'=?

constant angular acceleration equation is given by,

ωФ_Z= ωФ_o_z + αФ_Zt

αФ_Z= (ωФ_Z - ωФ_o_z )/t => (3.333-8.333)/4

αФ_Z= -1.25 rev/s²

θ-θФ_o = ωФ_o_z t + 1/2αФ_Zt²

      =(8.333)(4) + 1/2 (-1.25)(4)²

      =23.3 rev

b) ωФ_Z=0   (comes to rest)

ωФ_o_z = 3.333 rev/s

αФ_Z= -1.25 rev/s²

ωФ_Z= ωФ_o_z + αФ_Zt

t= (ωФ_Z - ωФ_o_z)/αФ_Z => (0- 3.333)/-1.25

t= 2.67s

3 0
2 years ago
A trio of students push a 65 kg crate. The first student pushes 31 N [e], the second student pushes 28 N [s] and the third stude
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Answer:

The free body diagram is attached.

Explanation:

A force of 31[N] to the east, the second force goes to the south and it is equal to 28[N], the third force goes to the west and it is equal to 39 [N].

We can consider the crate as a particle. And all the forces are acting over the particle.

5 0
3 years ago
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