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3 years ago

How would you describe your position using reference points?

Physics

2 answers:

Olin [163]3 years ago

8 0

Answer

A reference point is the starting point you choose to describe the location, or position, of an object. The reference point in the first example is your friend. ... The direction is north, and the reference point is your school. A position is an object's distance in a certain direction from a reference point.

Explanation:

kykrilka [37]3 years ago

4 0

Answer:

Hope this helps

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Can molecules with double or triple bonds twist

stiks02 [169]

Answer:

No.

Explanation:

The only way a twist may be done is if the trans form of an alkene/alkyne is twisted into the cis form--only if/when the pi bond is brokwn.

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3 years ago

If a car is traveling on the highway at a constant velocity, the force that pushes the car forward must be A. equal to the weigh

Gala2k [10]

the correct answer is c

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4 years ago

In which way are the cathode rays deflected in the x-plates of the Cathode Ray Oscilloscope

MrRissso [65]

Answer:

The cathode ray is deflected vertically to the fluorescent screen

Explanation:

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3 years ago

Read 2 more answers

Sort the forces as producing a torque of positive, negative, or zero magnitude about the rotational axis identified in part

Fantom [35]

a) Angular acceleration: $17.0 rad/s^2$

b) Weight: conterclockwise torque, reaction force: zero torque

Explanation:

In this problem, you are holding the pencil at its end: this means that the pencil will rotate about this point.

The only force producing a torque on the pencil is the weight of the pencil, of magnitude

$W=mg$

where m is the mass of the pencil and g the acceleration of gravity.

However, when the pencil is rotating around its end, only the component of the weight tangential to its circular trajectory will cause an angular acceleration. This component of the weight is:

$W_p =mg sin \theta$

where $\theta$ is the angle of the rod with respect to the vertical.

The weight act at the center of mass of the pencil, which is located at the middle of the pencil. So the torque produced is

$\tau = W_p \frac{L}{2}=mg\frac{L}{2} cos \theta$

where L is the length of the pencil.

The relationship between torque and angular acceleration $\alpha$ is

$\tau = I \alpha$ (1)

where

$I=\frac{1}{3}mL^2$

is the moment of inertia of the pencil with respect to its end.

Substituting into (1) and solving for $\alpha$ , we find:

$\alpha = \frac{\tau}{I}=\frac{mg\frac{L}{2}sin \theta}{\frac{1}{3}mL^2}=\frac{3 g sin \theta}{2L}$

And assuming that the length of the pencil is L = 15 cm = 0.15 m, the angular acceleration when $\theta=10^{\circ}$ is

$\alpha = \frac{3(9.8)(sin 10^{\circ})}{2(0.15)}=17.0 rad/s^2$

There are only two forces acting on the pencil here:

- The weight of the pencil, of magnitude $mg$

- The normal reaction of the hand on the pencil, R

The torque exerted by each force is given by

$\tau = Fd$

where F is the magnitude of the force and d the distance between the force and the pivot point.

For the weight, we saw in part a) that the torque is

$\tau =mg\frac{L}{2} cos \theta$

For the reaction force, the torque is zero: this is because the reaction force is applied exctly at the pivot point, so d = 0, and therefore the torque is zero.

Therefore:

- Weight: counterclockwise torque (I have assumed that the pencil is held at its right end)

- Reaction force: zero torque

8 0

3 years ago

The distance, x, covered by a particle in time, t, is given as x=a +bc+ct^2 +dt^3

Sav [38]

Answer:

$a$ has units of distance

$b$ has units of distance over time

$c$ has units of distance over $time^2$

$d$ has units of distance over $time^3$

Explanation:

Since the expression for the distance is:

$x = a+b\,t+c\,t^2+d\,t^3$

then:

$a$ has units of distance

$b$ has units of distance over time

$c$ has units of distance over $time^2$

$d$ has units of distance over $time^3$

because we are supposed to be able to add all of the terms and get a distance. So the products on each term that contains factors of time (t) should be cancelling those time units with units in the denominator of the multiplicative constant s that accompany them.

6 0

3 years ago