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zimovet [89]
3 years ago
5

A car starts from rest and accelerates uniformly over a time of 7.25 seconds for a distance of 210 m. Determine the acceleration

of the car. What is the variable Vi equal to?
Physics
1 answer:
lara31 [8.8K]3 years ago
8 0

Answer:

Acceleration is 7.990487515m/s²

Initial velocity is 0m.s

Explanation:

s=ut+(1/2)at²

210=0(7.25)+(1/2)a(7.25²)

210=26.28125a

∴a=7.990487515m/s²

'Vi' or 'u' is the inital speed. Since it starts from rest, this equals 0.

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5)A 0.50 kg hockey puck is at rest on ice when you hit it with a hockey stick, applying a force of 100 N for
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Answer:

F t = m Δv         impulse delivered = change in momentum

Δv = 100 * .1 / .5 = 20 m/s     original speed of puck

KE = 1/2 m v^2 = .5 * 20^2 / 2 = 100 J     initial KE of puck

E = μ m g d        energy lost by puck

Ff = μ m g = m a      deceleration of puck due to friction

a = μ  g = 9.8 * .2 = 1.96 m/s^2

v2 = a t + v1 = -1.96 * 4 + 20 = 12.2 m/s     speed of puck on striking box

m v2 = M V       conservation of momentum when puck strikes box

V = m v2 / M = 12.2 * .5 / .8 = 7.63 m/s     speed of box after collision

KE = 1/2 M V^2 = .8 * 7.63^2 / 2 = 23.3 J     KE of box after collision

KE = μ M g d     energy lost by box in sliding distance d

d = 23.3 / (.3 * .8 * 9.8) = 9.91 m     distance box slides

7 0
2 years ago
I need the answer with steps
Elis [28]

Answer: What Question

Explanation:

6 0
3 years ago
Consider a coil lying in the plane of the screen and the external magnetic field pointing into the screen. As the external magne
Margaret [11]

Answer:

The direction of the induced magnetic field should be pointing towards the screen.

Explanation:

Because the magnetic field is decreasing, and if we use Len's law, the induced current will increase the external magnetic field. For this increase to occur, said magnetic field produced by the induced current must be pointing towards the screen.

6 0
4 years ago
you push with an 18-N horizontal force on a 5-kg box of coffee resting on a on a horizontal surface. the force of friction on th
KatRina [158]

The acceleration is found to be 2 m/s², final velocity after 10 seconds is 20 m/s and the final position after 10 seconds is 100 m away from the starting point.

Answer:

Explanation:

As per Newton's second law of motion, acceleration of any object is directly proportional to the net external unbalanced force acting on that object and inversely proportional to the mass of the object.

Since there are two forces acting on the box in opposite direction, the net force will be the difference of horizontal and frictional force acting on the object.

Net force = Horizontal force - Frictional force = 18 N - 8 N = 10 N.

Now, from second law of motion, Acceleration = \frac{Net force}{Mass}

So, acceleration = 10 N /5 kg = 2 m/s².

Since, acceleration exerted by the box is found to be 2 m/s², we can determine the final velocity of the object after 10 seconds using the first equation of motion.

v = u + at, Here v is the final velocity and u is the initial velocity which is zero for the present case. Other parameters like a is found to be 2 m/s² and time is 10 seconds.

So Final velocity v = 0+(2×10)=20 m/s.

And the final position can be determined using the second equation of motion.

s = ut+1/2at²

Final position = (0×10)+(0.5×2×10×10)= 100 m.

So the final position is 100 m.

Thus, the acceleration is found to be 2 m/s², final velocity after 10 seconds is 20 m/s and the final position after 10 seconds is 100 m away from the starting point.

3 0
3 years ago
Briefly explain how a star produces its own heat and light.
salantis [7]

Stars give out heat and light due to continuous fusion and fission reaction of hydrogen and helium in it. These reactions release a tremendous amount of energy in the form of heat and light. helium atoms. During this process, huge amount of energy is released in the form of heat and light.

5 0
4 years ago
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