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Elenna [48]
3 years ago
13

how does the use of standard units of measurement solve problems in measurement regarding validity and reliabiility? explain it​

Physics
1 answer:
sukhopar [10]3 years ago
6 0

Answer:

Reliability can be estimated by comparing different versions of the same measurement. Validity is harder to assess, but it can be estimated by comparing the results to other relevant data or theory.

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A projectile is launched horizontally from a raised platform. If air resistance is ignored, then as the projectile falls to the
aliya0001 [1]

<h2>The option ( b ) is appropriate answer </h2>

Explanation:

When a projectile is projected from height horizontally . The only force acting upon it is the downwards gravitational force of attraction due to earth .

Due to this force its vertical component of velocity , which is in the downward direction will be increased .

As there is no force horizontally , the horizontal  velocity of throw will remain constant .

Thus ( b ) option is the correct option .

6 0
3 years ago
The knee extensors insert on the tibia at an angle of 30 degrees (from the longitudinal axis of the tibia), at a distance of 3 c
Reika [66]

Answer:

the knee extensors must exert 15.87 N

Explanation:

Given the data in the question;

mass m = 4.5 kg

radius of gyration k = 23 cm = 0.23 m

angle ∅ = 30°

∝ = 1 rad/s²

distance of 3 cm from the axis of rotation at the knee r = 3 cm = 0.03 m

using the expression;

ζ = I∝

ζ = mk²∝

we substitute

ζ = 4.5 × (0.23)² × 1

ζ  = 0.23805 N-m

so

from; ζ = rFsin∅

F = ζ / rsin∅

we substitute

F = 0.23805 / (0.03 × sin( 30 ° )

F = 0.23805 / (0.03 × 0.5)

F F = 0.23805 / 0.015

F = 15.87 N

Therefore, the knee extensors must exert 15.87 N

7 0
3 years ago
Salmon often jump waterfalls to reach their breeding grounds. Starting downstream, 2.33 m away from a waterfall 0.488 m in heigh
Ulleksa [173]

Answer:

5.68 m/s

Explanation:

The motion of the salmon is the same as a projectile: it is launched with an initial speed u at an angle of \theta=38^{\circ} above the horizontal.

The motion of the salmon consists of two indipendent motion:

- Along the horizontal direction, it is a uniform motion with constant velocity

v_x = u cos \theta

So that the distance travelled is

d=v_x t = u cos \theta t (1)

- Along the vertical direction, it is a uniformly accelerated motion with constant acceleration downward, so the vertical displacement is

y = u sin \theta t - \frac{1}{2}gt^2 (2)

where g is the acceleration of gravity.

We know the following:

- The horizontal distance travelled by the salmon to reach the waterfall is

d = 2.33 m

- The vertical distance travelled is the height of the waterfall,

y = 0.488 m

From (1) we get:

t=\frac{d}{u cos \theta}

And substituting into (2), we can solve the equation to find t, the time at which the salmon reaches the waterfall:

y = u sin \theta \frac{d}{u cos \theta} - \frac{1}{2}gt^2 = d tan \theta - \frac{1}{2}gt^2\\t = \sqrt{\frac{2(d tan \theta - y)}{g}}=\sqrt{\frac{2(2.33 tan 38^{\circ}-0.488)}{9.81}}=0.521 s

And then, we can use eq.(1) again to find the initial speed, u:

u=\frac{d}{cos \theta t}=\frac{2.33}{cos(38^{\circ})(0.521)}=5.68 m/s

5 0
3 years ago
Endometriosis, cysts, pelvic infections, and allergic reactions can all cause
gulaghasi [49]
D. Dyspareunia
I would say d because dyspareunia means painful sex so endometriosis, cyst, pelvic infections, and allergic reactions can all cause this.
5 0
3 years ago
In each of the four situations below an object is experiencing (nearly) uniform circular motion. State what force is providing t
Stells [14]

Answer:

Explanation:

Given that a centripetal force is a form of force that gives rise or causes a body to move in a curved path.

Hence;

1. When a car is being driven around a track, it is the FORCE OF FRICTION that is acting upon the turned wheels of the vehicle, which transforms into the centripetal force required for circular motion.

2. When a ball being is swung on the end of a string, TENSION FORCE acts upon the ball, which transforms the centripetal force required for circular motion.

3. When the moon is orbiting the earth, it is the FORCE OF GRAVITY acting upon the moon, which transforms the centripetal force required for circular motion.

4. A rotating wheel on the other hand has NO centripetal force because centripetal force is pull towards the center of a motion. However the speed of the object is tangent to the circle, while the direction of the force is also perpendicular to the direction of the rotating wheel.

4 0
3 years ago
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