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vova2212 [387]
3 years ago
8

3. A sprinter leaves the starting blocks with an acceleration of 4.5 m/s2. What is the

Physics
1 answer:
UkoKoshka [18]3 years ago
5 0

Hi there! :)

\large\boxed{v_{f} = 18 m/s}

Use the following kinematic equation to solve for the final velocity:

v_{f} = v_{i} + at

In this instance, the runner started from rest, so the initial velocity is 0 m/s. We can rewrite the equation as:

v_{f} = at

Plug in the given acceleration and time:

v_{f} = 4.5 * 4 = 18 m/s

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a car initially at rest can accelerate at 7 m/s^2 how long will it take the car to reach 60 m/s and how far will it travel durin
Alex787 [66]

1. The time taken for the car to reach a velocity of 60 m/s is 8.57 s

2. The distance travelled during the time is 257.14 m

<h3>What is acceleration? </h3>

The acceleration of an object is defined as the rate of change of velocity which time. It is expressed as

a = (v – u) / t

Where

  • a is the acceleration
  • v is the final velocity
  • u is the initial velocity
  • t is the time

1. How to determine the time

  • Initial velocity (u) = 0 m/s
  • Acceleration (a) = 7 m/s²
  • Final velocity (v) = 60 m/s
  • Time (t) =?

a = (v – u) / t

Thus,

t = (v – u) / a

t = (60 – 0) / 7

t = 8.57 s

2. How to determine the distance

  • Initial velocity (u) = 0 m/s
  • Acceleration (a) = 7 m/s²
  • Final velocity (v) = 60 m/s
  • Distance (s) = ?

v² = u² + 2as

60² = 0² + (2 × 7 × s)

3600 = 0 + 14s

3600 = 14s

Divide both sides by 14

s = 3600 / 14

s = 257.14 m

Learn more about acceleration and velocity:

brainly.com/question/491732

brainly.com/question/19466392

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7 0
1 year ago
An electric ceiling fan is rotating about a fixed axis with an initial angular velocity magnitude of 0.300 rev/s . The magnitude
Salsk061 [2.6K]

1) 1.2 m/s

First of all, we need to find the angular velocity of the blade at time t = 0.200 s. This is given by

\omega_f = \omega_i + \alpha t

where

\omega_i = 0.300 rev/s is the initial angular velocity

\alpha = 0.895 rev/s^2 is the angular acceleration

Substituting t = 0.200 s, we find

\omega_f = 0.300 + (0.895)(0.200)=0.479 rev/s

Let's now convert it into rad/s:

\omega_f = 2\pi \cdot 0.479 rev/s=3.01 rad/s

The distance of a point on the tip of the blade is equal to the radius of the blade, so half the diameter:

r=\frac{0.800}{2}=0.400 m

And so now we can find the tangential speed at t = 0.200 s:

v=\omega_f r =(3.01)(0.400)=1.2 m/s

2) 2.25 m/s^2

The tangential acceleration of a point rotating at a distance r from the centre of the circle is

a_t = \alpha r

where \alpha is the angular acceleration.

First of all, we need to convert the angular acceleration into rad/s^2:

\alpha = 0.895 rev/s^ \cdot 2 \pi =5.62 rad/s^2

A point on the tip of the blade has a distance of

r = 0.400 m

From the centre; so, the tangential acceleration is

a_t = (5.62)(0.400)=2.25 m/s^2

3) 3.6 m/s^2

The centripetal acceleration is given by

a=\frac{v^2}{r}

where

v is the tangential speed

r is the distance from the centre of the circle

We already calculate the tangential speed at point a):

v = 1.2 m/s

while the distance of a point at the end of the blade from the centre is

r = 0.400 m

Therefore, the centripetal acceleration is

a=\frac{1.2^2}{0.400}=3.6 m/s^2

7 0
3 years ago
When two objects collide, the momentum of the system remains constant. This is a statement of ______________.
Fudgin [204]
Conservation of momentum
3 0
3 years ago
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A water skier is pulled behind a boat. When the skis push down on the water, what is the reaction force?
IrinaVladis [17]
The answer is C) The water pushed up on the skis

The water reacts to the downward force of the skis by pushing back up against the skis. 
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3 years ago
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If you place one staple on an electronic balance, the balance still reads 0.0 grams. However, if you place
Tasya [4]
Mass of 1 staple = 6.8 g/210 staples
mass of 1 staple  = 0.032380952 g
Hope that helps!!
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3 years ago
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