All categories

3 years ago

A car starts from rest and accelerates uniformly to a speed of 72 km per hour over a distance of 500m. calculate acceleration

Physics

1 answer:

Kisachek [45]3 years ago

6 0

Answer:

0.4 m/s^2 or 5184 km/h^2

Explanation:

To find the acceleration, given the inicial and final speed of the car, we can use the Torricelli's formula:

V^2 = Vo^2 + 2*a*D

Where V is the final speed, Vo is the inicial speed, a is the acceleration and D is the distance travelled. So, with V = 72 km/h, Vo = 0 (starts from rest) and D = 0.5 km, we have:

72^2 = 0 ^2 + 2*a*0.5

a = 72^2 = 5184 km/h^2

For an acceleration in m/s^2, we should use the speed in meters per second (72 / 3.6 = 20 m/s) and the distance in meters (D = 500):

20^2 = 0^2 + 2*a*500

400 = 1000a

a = 0.4 m/s^2

You might be interested in

Each blade of a fan has a radius of 11 inches. If the fan’s rate of turn is 1440o /sec, find the following. (a) The angular spee

notka56 [123]

Answer:

a) 24.43 radians per second

b) 268.73 inches per second

Explanation:

a) The angular speed of the fan on Celsius degrees/second is 1400, so we should convert that value to radians using the fact that 2π rad = 360 °C:

$\omega = 1400\frac{C}{s}=1400\frac{C}{s}*\frac{2\pi\,rad}{360\,C}$

$\omega = 1400\frac{C}{s}=24.43\frac{rad}{s}$

b) Linear speed on a point of the blade is related with angular speed of the fan by the equation

$v=\omega r$

with v linear speed, ω angular speed and r the radius of the blades. So:

$v=(24.43\frac{rad}{s})(11 in)$

Radians isn't really a unity; it is dimensionless so we can put it or not. So:

$v=268.73\frac{in}{s}$

3 0

3 years ago

The apparent reversal of motion of planets against the backdrop of fixed stars is called

Free_Kalibri [48]

The planets move eastward against the background of fixed stars with the exception of Venus, Uranus and Pluto moving westward as seen in Earth's sky . This apparent retreating movement is called Retrograde motion. It is illusion created by Earth's movement going by outer planets in their respective orbits.

7 0

3 years ago

Read 2 more answers

A projectile is launched into the air with an initial speed of 40 m/s and a launch angle of 20° above the horizontal. The projec

miv72 [106K]

Explanation:

V=40m/s

Vy=V.sina=40.sin20=40 . 0.342=13.68m/s

Vx=V.cosa=40.cos20=40 . 0.766=30.64m/s

Projectile travels during 5 seconds and the ramge becomes:

x=V.t=30.64 . 5=153.2m

7 0

3 years ago

Alex is standing still and throws a football with a speed of 10 m/s to his friend, who is also standing still. The two friends a

Phantasy [73]

The question is incomplete. It comes with a set of answer choices.

These are the answer choices:

Alex observes it as 10 m/s, and his friend observes it as less than 10 m/s.

Alex observes it as less than 10 m/s, and his friend observes it as 10 m/s.

Both Alex and his friend observe it as 10 m/s.

Both Alex and his friend observe it as less than 10 m/s.

Answer: Both Alex and his friend observe it as 10 m/s.

Justification:

1) The speed is relative to the frame of reference.

2) It is said that the both Alex and his friend are standing still.

3) Then, the speed they both see is the same, 10 m/s, respect the Earth (where they are standing still).

Of course, Alex is watching the ball moving away and his friend is seing it approaching, but it is not relevant for the question, as it deals with the speed which is only about magnitude, not direction.

7 0

3 years ago

Read 2 more answers

Will a seismic wave traveling through a solid go slower or faster than a seismic wave traveling through a liquid? Why?

Snezhnost [94]

You can't answer this question because you aren't giving the specific type of seismic waves. There is an s-wave a p-wave and an l-wave. Those are the basic waves. An S-wave cannot travel through a liquid at all. So, obviously it travels slower than any other seismic wave.

<span>It would travel faster because their speed depends on the density and composition of material that they pass through.</span>

3 0

3 years ago

A car starts from rest and accelerates uniformly to a speed of 72 km per hour over a distance of 500m. calculate acceleration​

A car starts from rest and accelerates uniformly to a speed of 72 km per hour over a distance of 500m. calculate acceleration