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2 years ago

How many foot-pounds of work does it take to throw a baseball 90 mph? a baseball weighs 5 oz, or 0.3125 lb?

Physics

1 answer:

NARA [144]2 years ago

5 0

Kinetic energy of the ball is (mv²) / 2, where m is the mass and v is the velocity

So plugging in the mass and the velocity into the kinetic energy expression, you get:

Kinetic energy of the ball = (mv²) / 2

(0.3125/32) times (132)² divided by 2 = 85 ft-lbs

Kinetic energy of the ball = 85 ft-lbs

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Homework help plz it would help a lot

blagie [28]

#82

here we know that

acceleration = 2 m/s/s

time = 5 s

initial speed = 4 m/s

now we can use kinematics to find the final speed

$v_f = v_i + at$

$v_f = 4 + 2(5)$

$v_f = 14 m/s$

So correct answer will be option D)

#83

here we know that

acceleration = 3 m/s/s

time = 4 s

initial speed = 5 m/s

now we can use kinematics to find the final speed

$v_f = v_i + at$

$v_f = 5 + 3(4)$

$v_f = 17 m/s$

So correct answer will be option C)

#84

here we know that

acceleration = 7 m/s/s

time = 3 s

initial speed = 8 m/s

now we can use kinematics to find the final speed

$v_f = v_i + at$

$v_f = 8 + 7(3)$

$v_f = 29 m/s$

So correct answer will be option C)

6 0

3 years ago

According to one set of measurements, the tensile strength of hair is 196 MPa , which produces a maximum strain of 0.380 in the

slega [8]

Answer:

(a). The magnitude of the force is 0.38416 N.

(b). The original length is 0.0869 m.

Explanation:

Given that,

Tensile strength = 196 MPa

Maximum strain = 0.380

Diameter = 50.0 μm

Length = 12.0 cm

We need to calculate the area

Using formula of area

$A=\dfrac{\pi}{4}\times d^2$

Put the value into the formula

$A=\dfrac{\pi}{4}\times(50.0\times10^{-6})^2$

$A=1.96\times10^{-9}\ m^2$

We need to calculate the magnitude of the force

Using formula of force

$F=\sigma A$

Put the value into the formula

$F=196\times10^{6}\times1.96\times10^{-9}$

$F=0.38416\ N$

(b). If the length of a strand of the hair is 12.0 cm at its breaking point

We need to calculate the unstressed length

Using formula of strain

$strain=\dfrac{\Delta l}{l_{0}}$

$\Delta l=strain\times l_{0}$

Put the value into the formula

$\Delta l=0.380\times l_{0}$

Length after expansion is 12 cm

We need to calculate the original length

Using formula of length

$l=l_{0}+\Delta l$

Put the value into the formula

$I=l_{0}+0.380\times l_{0}$

$l=1.38l_{0}$

$l_{0}=\dfrac{l}{1.38}$

$l_{0}=\dfrac{12\times10^{-2}}{1.38}$

$l_{0}=0.0869\ m$

Hence, (a). The magnitude of the force is 0.38416 N.

(b). The original length is 0.0869 m.

4 0

3 years ago

What are the possible units for a spring constant

AleksAgata [21]

Hooke's Law says that F=-kx where k is the spring constant measured in N/m (newtons per meter)

5 0

3 years ago

Read 2 more answers

What is the economic application of change of state

Musya8 [376]

It is based on their state like population, literacy and poverty it varies from state to state, country to country

7 0

2 years ago

Inside most ball-point pens is a small spring that compresses as the pen is pressed against the paper. If a force of 0.1 N compr

AnnZ [28]

Answer:

20 N/m

Explanation:

From the question,

The ball-point pen obays hook's law.

From hook's law,

F = ke............................ Equation 1

Where F = Force, k = spring constant, e = compression.

Make k the subject of the equation

k = F/e........................ Equation 2

Given: F = 0.1 N, e = 0.005 m.

Substitute these values into equation 2

k = 0.1/0.005

k = 20 N/m.

Hence the spring constant of the tiny spring is 20 N/m

8 0

2 years ago