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3 years ago

Someone help me I will mark brainless it’s 2 questions .

Physics

1 answer:

AveGali [126]3 years ago

5 0

Answer:

1.C,2.A

Explanation:

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You are driving at the speed of 33.4 m/s (74.7296 mph) when suddenly the car in front of you (previously traveling at the same s

romanna [79]

Answer:

Part a)

a = - 8.45 m/s/s

Part b)

$d = 66 m$

Part c)

$d = 14.16 m$

Explanation:

Part a)

when car apply brakes then the friction force on the car in front of us is given as

$F_f = \mu mg$

here we need to find deceleration due to friction

$a = \frac{F_f}{m}$

$a = -\mu g$

$a = -8.45 m/s^2$

Part b)

Braking distance of the car is the distance that it move till it stops

so we will have

$v_f^2 - v_i^2 = 2ad$

$0 - 33.4^2 = 2(-8.45)d$

$d = 66 m$

Part c)

Since we know that average reaction time for human is 0.424 s

now we know that during reaction time our car will travel at uniform speed

so we will have

$d = vt$

$d = (33.4) (0.424)$

$d = 14.16 m$

4 0

3 years ago

The deepest section of ocean in the world is the Marianas Trench, located in the Pacific Ocean. Here the ocean floor is as low a

Levart [38]

B I just took the test

3 0

2 years ago

A ladder 10 ft long rests against a vertical wall. If the bottom of the ladder slides away from the wall at a rate of 1.4 ft/s,

Art [367]

Answer:

$\dfrac{d\theta}{dt} =-0.233\ rad/s$

Explanation:

given,

length of ladder = 10 ft

let x be the distance of the bottom and y be the distance of the top of ladder.

x² + y² = 100

differentiating with respect to time we get

$2 x\dfrac{dx}{dt}+2y\dfrac{dy}{dt} = 0$ ..............(1)

when x = 8 and y = 6 and when \dfrac{dx}{dt} = 1.4ft/s

from equation (1)

now,

$16\times 1.4 + 12\dfrac{dy}{dt} = 0$

$\dfrac{dy}{dt} = -\dfrac{5.6}{3}$

let the angle between the ladders be θ

$tan\theta = \dfrac{y}{x}$

y = xtan θ

$\dfrac{dy}{dt} =\dfrac{dy}{dt} tan\theta + x sec^2\theta\dfrac{d\theta}{dt}$

$-\dfrac{5.6}{3} =1.4\times \dfrac{6}{8} + 8 (1+\dfrac{9}{16})\dfrac{d\theta}{dt}$

$\dfrac{25}{2} \dfrac{d\theta}{dt} =\dfrac{-17.5}{6}$

$\dfrac{d\theta}{dt} =-0.233\ rad/s$

6 0

3 years ago

Why gravitational force at the center og earth is zero

KengaRu [80]

F = G Mm/r²
mg = G Mm/r²
g = GM/r²
At centre of earth, r=0
g = GM/0
g =0

8 0

3 years ago

Read 2 more answers

A long electric cable is suspended above the earth and carries a current of 345 A parallel to the surface of the earth. The eart

jok3333 [9.3K]

Answer:

0.906 N

Explanation:

Formula for magnetic force acting on current carrying cable:

$F = IBLsin(\theta)$

Where I = 345A is the current in the wire, B = $5.6*10^{-5} T$ is the magnetic magnitude generated by Earth. L = 46.9 m is the cable length. $\theta = 88.2^o$ is the angle between vector B and cable direction.

$F = 345*5.6*10^{-5}*46.9*sin(88.2^o)$

$F = 0.906 N$

7 0

3 years ago