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2 years ago

Two identical cars, each traveling at the same velocity, and having the same mass come to a stop

Physics

1 answer:

olya-2409 [2.1K]2 years ago

4 0

Answer:

The second option - same change in momentum, different force

Explanation:

They experience the same change in momentum, but the force on car A is greater.

p=m*v

Impulse, or change in p=F*t

We know the cars have the same change in momentum, because they both go from the same initial momentum (p=mv), to zero momentum. Therefore, both experience the same change in momentum. Since the time is different, but the change in momentum is the same, the force has to be different.

For example: if both cars had 200 kg*m/s of momentum at the start, and 0 at rest, the impulse is 200 kg*m/s

So,

p(a)= 200=F(0.3)

p(b)= 200=F(5)

Which force has to be greater to make the equations true? The force for Car A, of course!

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The effect of mechanical work on an object is _. (complete the sentence.)

Advocard [28]

Answer:

Displacement (i.e. change in its final position)

Explanation:

In classical mechanics work is described as the displacement of the body in the direction of the applied force.

<u>Mathematically given as:</u>

$W=F.s\ cos\ \theta$

where:

F = force on the body

s = displacement of the body

θ = angle between the force and direction of displacement

While force, acceleration, velocity can also be the answer for the blank space but the displacement effect is visible during and even after the work has been done, so one can notice the change in position of the object even when the person has not seen the process but just the initial condition of the body.

8 0

3 years ago

a bicyclist travels with an averahe velocity of 15km/h north, for 20 minutes .what is his displacement ?

Lunna [17]

Explanation:

velocity = 15 km/hr = 15×1000m / 60×60s

= 4.17 m/s

time= 20 min= 20 × 60s

= 1200s

displacement =?

we know that,

V = D / t

or, 4.17 = D / 1200

or, D = 4.17 × 1200

or,D = 5004 m

7 0

2 years ago

an automobile is traveling 65km/h the brakes decelerate it at a rate of -6.0 m/s^2 how long will it take to stop the car?

joja [24]

Explanation:

It is given that,

Initial speed of the automobile, u = 65 km/hr =

Final speed of the automobile, v = 0

Deceleration of the automobile, $a=-6\ m/s^2$

We need to find the distance covered by the car as it comes to rest. It can be calculated using third equation of motion as :

$v^2-u^2=2ax$

$a=\dfrac{v^2-u^2}{2x}$

$a=\dfrac{0-(18.05)^2}{2\times (-6)}$

$a=27.15\ m/s^2$

So, the acceleration of the car is $27.15\ m/s^2$ . Hence, this is the required solution.

6 0

3 years ago

Consider a composite cube made of epoxy with fibers aligned along one axis of the cube (the fibers are parallel to four of the t

coldgirl [10]

The question is incomplete. The complete question is :

Consider a composite cube made of epoxy with fibers aligned along one axis of the cube (the fibers are parallel to four of the twelve cube edges). If the cube can only be loaded in axial tension such that the force is uniformly applied over - and is normal to - a cube face, what is the lowest possible positive length change the cube can experience under this tension? The applied tensile force is 102 KN. The unloaded cube edge length is 56 mm. The glass fibers have an elastic modulus of 200 GPa. The epoxy has an elastic modulus of 38 GPa. The cube is comprised of 18 vol% epoxy (the balancing vol % is glass fiber). Hint: The loading axis is intentionally unspecified. Answer Format: Lowest possible length increase (change of length) under tension.

Solution :

Given :

$E_{glass fibre}$ = 200 GPa