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If a ball is thrown vertically upward with a velocity of 160 ft/s, then its height after t seconds is s = 160t − 16t^2.

White raven [17]

Answer:

400ft. 32ft/s -32ft/s

Explanation:

In reality the gravitational acceleration is 9.81 so the quadratic coefficient of the function should be 9.81/2

Anyway for the sake of assumtion let us takes=160t-16t^2

ds/dt=160-32t=0

t=160/32= 5 seconds.

s=160*160/32-16*(160/32)^2= 400 mts

s=384 mts

160t-16t^2=384

i.e

16t^2-160t+384=0

t^2-10t+24=0

(t-6)(t-4)=0

t=[4,6]

we have to take t=4 because it is all the up i.e <5

velocity =v=ds/dt=160-32t

v=160-32*4=32 ft/sec still going up

for all the way down take t=6 whuch is >5

v=160-6*32=-32 ft/sec (falling down!!!)

6 0

3 years 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

(b) Can the speed of a rocket exceed the exhaust speed of the fuel? Explain.

muminat

<u>Yes. The speed of a rocket can exceed the exhaust speed of the fuel.</u>

How this is explained?

The thrust of the rocket does not depend on the relative speed of the gases or the relative speed of the rocket.
It depends on conservation of momentum.

What is conservation of momentum?

Conservation of momentum, general law of physics according to which the quantity called momentum that characterizes motion never changes in an isolated collection of objects; that is, the total momentum of a system remains constant.

Momentum is equal to the mass of an object multiplied by its velocity and is equivalent to the force required to bring the object to a stop in a unit length of time.
For any array of several objects, the total momentum is the sum of the individual momenta.
There is a peculiarity, however, in that momentum is a vector, involving both the direction and the magnitude of motion, so that the momenta of objects going in opposite directions can cancel to yield an overall sum of zero.

To know more about conservation of momentum, refer:

brainly.com/question/7538238

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4 0

2 years ago

during a workout, a football player pushes a blocking dummy a distance of 30 m. while pushing the dummy the same distance a seco

babymother [125]

$Power=\frac{Work}{Time}=\frac{Force\times distance}{time}$

If he wants to increase power, force must increase and decrease time.

8 0

3 years ago

Read 2 more answers

Use ideas of electromagnetic induction to explain how the input voltage is transformed into an output voltage

devlian [24]

With the help of a transformer input voltage is transformed into an output voltage

<h3>What is induced voltage?</h3>

Electromagnetic induction is what causes the induced voltage. Electromagnetic induction is the process of generating emf (induced voltage) by subjecting a conductor to a magnetic field.

In this case, a magnet is pushed in and out of a wire coil attached to a high-resistance voltmeter.

Typically, a transformer's primary winding is attached to the input voltage source and changes electrical power into a magnetic field.

The secondary winding's role is to turn this alternating magnetic field into electricity, generating the necessary output voltage.

Hence with the help of a transformer input voltage is transformed into an output voltage.

To learn more about the induced voltage refer to the link;

brainly.com/question/19482771

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5 0

2 years ago