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2 years ago

What is necessary to designate a position? A. a reference point B. a direction C. fundamental units D. motion E. all of these

Physics

1 answer:

max2010maxim [7]2 years ago

8 0

Answer:

E. all of these

Explanation:

The designation of a point in space all the points that necessary

- reference point

- a direction

- fundamental units

- a direction

- motion

all are necessary to designate a point in space. Hence option E is correct.

For example in simple harmonic motion we need to specify all the above factors of the object in order to designate the position of the object.

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a fan acquires a speed of 180 rpm in 4s, starting from rest. calculate the speed of the fan at the end of the 5th second startin

KengaRu [80]

Answer:

225 rpm

Explanation:

The angular acceleration of the fan is given by:

$\alpha = \frac{\omega_f - \omega_i}{\Delta t}$

where

$\omega_f$ is the final angular speed

$\omega_i$ is the initial angular speed

$\Delta t$ is the time interval

For the fan in this problem,

$\omega_i = 0\\\omega_f = 180 rpm\\\Delta t=4 s$

Substituting,

$\alpha = \frac{180-0}{4}=45 rpm/s$

Now we can find the angular speed of the fan at the end of the 5th second, so after t = 5 s. It is given by:

$\omega' = \omega_i + \alpha t$

where

$\omega_i = 0\\\alpha = 45 rpm/s\\t = 5 s$

Substituting,

$\omega' = 0 + (45)(5)=225 rpm$

7 0

2 years ago

Little Timmy wants to measure how tall his house is. He doesn’t have a tape measure but does have a stopwatch. He recruits Big B

Komok [63]

The distance covered by an object accelerating from rest is

D = (1/2) · (acceleration) · (time)² .

In this particular case, 'acceleration' is 9.8 m/s² ... due to gravity.

D = (1/2) · (9.8 m/s²) · (1.67 s)²

D = (4.9 m/s²) · (2.789 s²)

D = 13.67 meters

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2 years ago

The elastic energy stored in your tendons can contribute up to 35 % of your energy needs when running. Sports scientists have st

irina [24]

Complete Question:

The elastic energy stored in your tendons can contribute up to 35 % of your energy needs when running. Sports scientists have studied the change in length of the knee extensor tendon in sprinters and nonathletes. They find (on average) that the sprinters' tendons stretch 43 mm , while nonathletes' stretch only 32 mm . The spring constant for the tendon is the same for both groups, $31 {\rm {N}/{mm}}$ . What is the difference in maximum stored energy between the sprinters and the nonathlethes?

Answer:

$\triangle E = 12.79 J$

Explanation:

Sprinters' tendons stretch, $x_s = 43 mm = 0.043 m$

Non athletes' stretch, $x_n = 32 mm = 0.032 m$

Spring constant for the two groups, k = 31 N/mm = 3100 N/m

Maximum Energy stored in the sprinter, $E_s = 0.5kx_s^2$

Maximum energy stored in the non athletes, $E_m = 0.5kx_n^2$

Difference in maximum stored energy between the sprinters and the non-athlethes:

$\triangle E = E_s - E_n = 0.5k(x_s^2 - x_n^2)\\\triangle E = 0.5*3100* (0.043^2 - 0.032^2)\\\triangle E = 0.5*31000*0.000825\\\triangle E = 12.79 J$

4 0

3 years ago

The fulcrum of a first-class lever divides its 9.0 m arm into two sections—a 6.0 m arm and a 3.0 m arm. You place a rock weighin

nexus9112 [7]

For balancing the lever, force on both the sides shall be equal. so,
Force on 3 m end = m × a = 3 × 98.1 = 294.3

Now, on 6 m end, it would be: = 294.3/6 = 49.05
After rounding-off to the nearest hundredth value, it would be: 49 N

Finally, Option A would be your correct answer.

Hope this helps!

6 0

2 years ago

Betty hits a baseball.

lorasvet [3.4K]

Answer:

point 2

Explanation:

5 0

2 years ago