Why is an absorption spectrum especially useful for astronomers?.

A football quarterback throws a football for a long pass. While in the motion of throwing, the quarterback moves the ball , star

sergejj [24]

This question is incomplete, the complete question is;

A football quarterback throws a 0.408 kg football for a long pass. While in the motion of throwing, the quarterback moves the ball 1.909 m, starting from rest, and completes the motion in 0.439 s. Assuming the acceleration is constant, what force does the quarterback apply to the ball during the pass ;

a) F_throw = 8.083 N

b) F_throw = 9.181 N

c) F_throw = 2.284 N

d) F_throw = 16.014 N

e) None of these is correct

Answer:

the quarterback applied a force of 8.083 N to the ball during the pass

so Option a) F_throw = 8.083 N is the correct answer

Explanation:

Given that;

m = 0.408 kg

d = 1.909 m

u = 0 { from rest}

t = 0.439 s

Now using Kinetic equation

d = ut + 1/2 at²

we substitute

1.909 = (0 × 0.439) + 1/2 a(0.439)²

1.909 = 0 + 0.09636a

1.909 = 0.09636a

a = 1.909 / 0.09636

a = 19.8111 m/s²

Now force applied will be;

F = ma

we substitute

F = 0.408 × 19.8111

F = 8.0828 ≈ 8.083 N

Therefore the quarterback applied a force of 8.083 N to the ball during the pass

so Option a) F_throw = 8.083 N is the correct answer

5 0

3 years ago

A tortoise and hare start from rest and have a race. As the race begins, both accelerate forward. The hare accelerates uniformly

Mnenie [13.5K]

Answer:

The acceleration of the hare once it begins to slow down is -0.68 m/s²

The acceleration of the tortoise is 0.28 m/s²

Explanation:

The equations that describe the position and velocity of the hare and the tortoise are the following:

x = x0 + v0 · t + 1/2 · a · t²

v = v0 + a · t

Where:

x = position at time t

x0 = initial position

v0 = initial velocity

t = time

a = acceleration

v = velocity at time t

To find the acceleration of the hare once it begins to slow down, we have to find how much time the hare traveled during the deceleration and what was its initial speed.

First, the hare moves with constant acceleration for 4.7 s. Then, its velocity at t = 4.7 s will be:

v = v0 + a · t (v0 = 0 because the hare starts form rest)

v = a · t = 0.9 m/s² · 4.7 s = 4.2 m/s

The distance traveled by the hare while accelerating can be calculated using the equation of the position:

x = x0 + v0 · t + 1/2 · a · t² (x0 = 0 and v0 = 0)

x = 1/2 · a · t² = 1/2 · 0.9 m/s² · (4.7)² = 9.9 m

Then, the hare runs at a constant speed of 4.2 m/s for 11.7 s. The distance traveled at constant speed will be:

x = v · t

x = 4.2 m/s · 11.7 s = 49.1 m

Then, the distance traveled by the hare while slowing down was:

Distance traveled while slowing down = 72 m - 49.1 m - 9.9 m = 13 m

Let´s find how much time it took the hare to come to stop, so we can calculate the acceleration. We know that when the position is 13 m, the velocity is 0.

v = v0 + a · t

0 = 4.2 m/s + a · t

-4.2 m/s / t = a

Replacing in the equation of the position:

x = v0 · t + 1/2 · a · t² (considering x0 as the point at which the hare started to slow down)

13 m = 4.2 m/s · t - 1/2 · 4.2 m/s / t · t²

13 m = 4.2 m/s · t - 2.1 m/s · t

13 m = 2.1 m/s · t

t = 13 m / 2.1 m/s

t = 6.2 s

Then, the acceleration of the hare while slowing down will be:

-v0/t = a

-4.2 m/s / 6.2 s = a

a = -0.68 m/s²

The acceleration of the hare once it begins to slow down is -0.68 m/s²

The hare traveled 72 m in (6.2 s + 11.7 s + 4.7 s) 22.6 s. The tortoise reaches the final position of the hare at the same time, so, using the equation of the position we can calculate the acceleration of the tortoise:

x = x0 + v0 · t + 1/2 · a · t² (x0 = 0 and v0 = 0)

x = 1/2 · a · t²

72 m = 1/2 · a · (22.6 s)²

144 m / (22.6 s)² = a

a = 0.28 m/s²

The acceleration of the tortoise is 0.28 m/s²

6 0

3 years ago

You are looking down on a 20 kg beam resting on a horizontal, frictionless surface. The beam is 2 m long and can pivot about one

Korolek [52]

The angular speed of the rod after the impact is 1.49 rad/s

What is angular speed?

The rate of change of angular displacements is known as angular speed.

Angular speed is a scalar measure of the rotating object.

What is Angular momentum?

It is the property of a rotating body given by the product of the moment of inertia and the angular velocity of the rotating object.

Angular momentum is expressed as follows:

L=m*v*r

Here,

mass of beam, M =20 kg

mass of rock, m =0.1 kg

length of the beam, L =2 m

length where rock slides, l = (L / 2), l = 1 m

velocity of rock, v =400 m/s

As here the Torque on which the system is zero implies that the angular momentum is conserved.

Initial angular momentum for rock: I(ri) = m*v*r

Final angular momentum for rock: I(rf) = m*w*r^2

Final angular momentum for beam: I(bf) = 1/3 (M*L^2w)

Now, According to the conservation of momentum:

m*v*r = m*w*r^2 + 1/3 (ML^2w)

w = m*v*r / ( mr^2 + 1/3 ML^2 )

w = 0.1 *400*1 / ( (0.1 * 1) + 1/3 20* 2^2 )

w = 1.49 rad / s

The angular speed of the rod after the impact is 1.49 rad/s

Learn more about Angular speed here:

brainly.com/question/14663644

#SPJ4

6 0

2 years ago

A pipe open at both ends resonates at a fundamental frequency fopen. When one end is covered and the pipe is again made to reson

xz_007 [3.2K]

Answer:

option (1)

Explanation:

fundamental frequency of open pipe, fopen = v/2L

fundamental frequency of closed pipe, f closed = v / 4L

By dividing both of them

f open = 2 x f closed

f open = two times f closed

f closed = 1 / 2 x f open

8 0

3 years ago

Which of the following situations correctly describes power? Bill pushed a car for 5 minutes for 20-km while doing 15 J of work.

xxMikexx [17]

I'm warning you before i answer this i'm not guaranteeing i'm going to answer this wright but I'm pretty sure its bill pushed a car for 5 minutes for 20-km while doing 15 J of work. Why I think this is the answer is because it directly tells you the most information giving you the time it took him to move the object that distance and also telling you how many joule's of force he's exerting (power).
Hope this helped :)

6 0

4 years ago