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3 years ago

An object moving in a straight line is decelerating. Which about its acceleration is necessarily true?

Physics

1 answer:

Varvara68 [4.7K]3 years ago

3 0

Answer:

Its acceleration is certainly negative.

Explanation:

When an object moving in a straight line decelerates then its velocity certainly decreases.

Its acceleration is certainly negative.

As we know that acceleration is the rate of change in velocity and the object is decelerating i.e. its velocity is reducing with time.

$a=\frac{v_f-v_i}{t_f-t_i}$

where:

$v_f\ \&\ v_i$ are final and initial velocities of the object

$t_f\ \&\ t_i$ are final and initial time of observation.

Its SI unit is $m.s^{{-2}$

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What is the most important safety rule in cycling?

Mekhanik [1.2K]

Answer:

Wear a helmet. Stay visible; use bike lights and/or wear bright clothes. Look and Signal; use hand signals to let drivers know where you're going, try to make eye contact with them and look before you go.

Explanation:

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3 years ago

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another way, speed is a scalar value, while reloolg isa Which ONE of the following represents a toy car that moves at a higher a

erica [24]

Car A will have highest speed is 83.3m/s .

<h3>What is speed ? </h3>

The rate of change of position of an object in any direction.

The S.I unit is m/s . Speed is a scalar quantity it defines only magnitude not direction

speed = distance /time

In case of Car A ,

We have given distance 150Km in 3 min ,

First we have convert the distance km to m

150×1000m

then conversion of min to sec

38×60sec

speed = 15000/180

speed = 83.3m/sec

In case of Car B

we have given 800m in 150 min

lets convert the time into second

150×60

Speed = 800/150×60

speed = 0.88m/ s

In case of Car C

We have given here distance 250 Km and time in 8 hours

convert km to m

25000

and time into sec

88×60×60

speed = 0.86m/ s

Hence ,Car A has highest speed amongst them .

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1 year ago

What is the density of an object with a mass of 60g and a volume of 2cm3?

zaharov [31]

m= 60g = 60/1000 Kg = 0.06 Kg v = 2cm3 = 2 * (0.01^3) m3 = 2 *10^-6 m3 Density= m/v = 6 * 10^-2 / 2 *10^-6 = 3 *10^4 Kg/m3

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3 years ago

To obtain your Class E learner's license, you'll need to _____.

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The answer is B.....

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3 years ago

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A punter drops a 2.0 kg ball from rest vertically 1 meter down onto his foot. The ball leaves the foot with a speed of 18 m/s at

pav-90 [236]

Answer:

Explanation:

Given

mass of drop $m=2 kg$

height of fall $h=1 m$

ball leaves the foot with a speed of 18 m/s at an angle of $55^{\circ}$

Velocity of ball just before the collision with the floor

$u^=2gh$

$u=\sqrt{2gh}$

$u=\sqrt{2\times 9.8\times 1}=4.42 m/s$

Impulse delivered in Y direction

$J_y=m(v\sin (55)-(-u))$

$J_y=2(18\sin (55)+4.42)$

$J_y=38.32 kg-m/s$

Impulse in x direction

$J_x=m\times v\cos (55)$

$J_x=2\times 4.42\cos (55)=20.646$

$J_{net}=\sqrt{J_x^2+J_y^2}$

$J_{net}=\sqrt{(38.32)^2+(20.64)^2}$

$J_{net}=43.52 kg-m/s$

at an angle of $\tan \phi =\frac{J_y}{J_x}=\frac{38.32}{20.64}$

$\phi =tan^{-1}(1.856)$

$\phi =61.7^{\circ}$

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3 years ago