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3 years ago

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A 2100 kg car starts from rest and accelerates at a rate of 2.6 m/s2 for 4.0 s. Assume that the force acting to accelerate the c

ar is acting in the same direction as its motion. How much work has the car done?

1 answer:

Reika [66]3 years ago

8 0

When the system is experiencing a uniformly accelerated motion, there are a set of equations to work from. In this case, work is energy which consist solely of kinetic energy. That is, 1/2*m*v2. First, let's find the final velocity.

a = (vf - v0)/t
2.6 = (vf - 0)/4
vf = 10.4 m/s

Then W = 1/2*(2100 kg)*(10.4 m/s)2
W = 113568 J = 113.57 kJ

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Circular Motion does occur on earth, so yes, true

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Answer:

A) 17.7 m/s

B) 15.98 m

C) Zero

E) 9.8 m/s²

Explanation:

given information

distance, h = - 34 m

time, t = 5 s

A) What is the initial speed of the egg?

h - h₀ = v₀t - $\frac{1}{2} g$ t², h₀ = 0

- 34 = v₀ 5 - \frac{1}{2} 9.8 5²

- 34 = 5 v₀ - 122.5

v₀ = 122.5 - 34/5

= 17.7 m/s

B) How high does it rise above its starting point?

v² = v₀² - 2gh

v = 0 (highest point)

2gh = v₀²

h = v₀²/2g

= 17.7²/2 (9.8)

= 15.98 m

C) What is the magnitude of its velocity at the highest point?

v = 0 (at highest point)

E) What are the magnitude and direction of its acceleration at the highest point?

g= 9.8 m/s², since the egg is moved vertically, the acceleration is the same as the gravitational acceleration.

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3 years ago

A baseball pitcher throws a ball at 97.0 mi/h in the horizontal direction. How far does the ball fall vertically by the time it

mario62 [17]

Answer:

Explanation:

1 mile=5280 ft

1 hour=3600 seconds

Changing speed from mi/h to ft/s

$97 mi/h \times \frac {5280}{3600}=142.2666667 ft/s\approx 142.27 ft/s$

Time of flight, $t=\frac {distance}{speed}=\frac {60.5}{142.27}=0.425257732 s\approx 0.425 s$

From fundamental kinematics equations

$h=0.5gt^{2}$ where g is acceleration due to gravity whose value is taken as 32.2 ft/s2 and h is the distance

By substitution

$h=0.5\times 32.2\times 0.425^{2}=2.9080625 m\approx 2.91 m$

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3 years ago

What is the STANDARD unit of measurement for velocity in Physics?

rusak2 [61]

Answer:

$m. {s}^{ - 1}$

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2 years ago

The tub of a washer goes into its spin-dry cycle, starting from rest and reaching an angular speed of 5.0 rev/s in 8.0 s. At thi

alisha [4.7K]

Answer:

The total number of revolution is 50 rev.

Explanation:

Given that,

Angular speed = 5.0 rev/s

Time = 8.0 s

We need to calculate the angular acceleration

Using equation of angular motion

$\omega_{f}-\omega_{i}=\alpha t$

Put the value into the formula

$5.0-0=\alpha\times8.0$

$\alpha=\dfrac{5.0}{8.0}$

$\alpha=0.625\ rev/s^2$

We need to calculate the angular displacement

Using equation of angular motion

$\theta=\omega_{i}t+\dfrac{1}{2}\alpha t^2$

Put the value into the formula

$\theta=0+\dfrac{1}{2}\times0.625\times(8.0)^2$

$\theta=20\ rev$

Now, The washer coming to rest from top spin

We need to calculate the angular acceleration

Using equation of angular motion

$\omega_{f}-\omega_{i}=\alpha t$

$\alpha=\dfrac{\omega_{f}-\omega_{i}}{t}$

$\alpha=\dfrac{0-5}{12}$

$\alpha=−0.4167\ rev/s^2$

We need to calculate the angular displacement

Using formula of displacement

$\theta'=\omega_{i}t+\dfrac{1}{2}\alpha t^2$

Put the value into the formula

$\theta'=5\times12+\dfrac{1}{2}\times(-0.4167)\times12^2$

$\theta'=30\ rev$

We need to calculate the total number of revolution

$\theta''=\theta+\theta'$

$\theta''=20+30$

$\theta''=50\ rev$

Hence, The total number of revolution is 50 rev.

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3 years ago