All categories

3 years ago

If you get a ticket for speeding, it is based on your average speed or instantaneous speed? Explain

Physics

1 answer:

bagirrra123 [75]3 years ago

5 0

Answer:

Instantaneous speed

Explanation:

Usually the speed measuring guns are used to measure the speed at a certain instant, so the measured speed is instantaneous.

The average speed is determined by the expression final distance minus initial distance divided by time

$v_{aver} =\frac{x_{f}- x_{i}}{t}$

The instantaneous speed is determined in the same way as the average, but with the exception that the travel displacements are shorter (very close one each other).

You might be interested in

A ring is attached at the center of the underside of a trampoline. A sneaky teenager crawls under the trampoline and uses the ri

Karo-lina-s [1.5K]

Answer:

Explanation:

Given

Mass of mother $m=79\ kg$

Mother is released with a speed of $v=2.5\ m/s$

Assuming we need to find elastic Potential energy stored in Trampoline

Kinetic energy acquired by Mother comes from Elastic Potential Energy stored in the spring

I.e. Elastic Potential Energy=Kinetic Energy of mother

$\frac{1}{2}kx^2=\frac{1}{2}mv^2$

$E=\frac{1}{2}\times 79\times 2.5^2=246.875\ J$

So 246.875 J of Energy is stored in the trampoline as he pull the ring

5 0

3 years ago

A student sits on a rotating stool holding two 3.09-kg masses. When his arms are extended horizontally, the masses are 1.08 m fr

schepotkina [342]

Answer:

The New angular speed is $w_f = 2.034 rad/s$

The Kinetic energy before the masses are pulled in is $KE_i = 3.101 \ J$

The Kinetic energy after the masses are pulled in is $KE_f = 8.192 \ J$

Explanation:

From the we are told that masses are 1.08 m from the axis of rotation, this means that

The radius $r =1.08m$

The mass is $m = 3.09\ kg$

The angular speed $w = 0.770 \ rad/sec$

The moment of inertia of the system excluding the two mass $I = 3.25 \ kg \cdot m^2$

New radius $r_{new} = 0.34m$

Generally the conservation of angular momentum can be mathematical represented as

$w_f = [\frac{I_i}{I_f} ]w_i .....(1)$

Where $w_f$ is the final angular speed

$w_i$ is the initial angular speed

$I_i$ is the initial moment of inertia

$I_f$ is the final moment of inertia

Moment of inertia is mathematically represented as

$I = m r^2$

Where I is the moment of inertia

m is the mass

r is the radius

So the Initial moment of inertia is given as

$I_i = moment \ of \ inertia \ of\ the \ two \ mass \ + 3.25 \ kg \cdot m^2$

$I_i = 2m r^2 + 3.25$

The multiplication by is because we are considering two masses

$I_i = 2 [(3.09)(1.08)^2] +3.25 = 10.46 kg \cdot m^2$

So the final moment of inertia is given as

$I_f = 2[(3.09)(0.34)^2] +3.25 = 3.96 \ kg \cdot m^2$

Substituting these values into equation 1

$w_f = [\frac{10.46}{3.96} ] * 0.77 = 2.034 \ rad/sec$

Generally Kinetic energy is mathematically represented in term of moment of inertia as

$KE = \frac{1}{2} * I * w^2$

Now considering the kinetic energy before the masses are pulled in,

$KE_i = \frac{1}{2} * I_i * w^2_i$

The Moment of inertia would be $I_i = 10.46 \ Kg \cdot m^2$

The Angular speed would be $w_i = 0.77 \ rad/s$

Now substituting these value into the equation above

$KE_i = \frac{1}{2} * (10.46) * (0.770)^2 = 3.101 J$

Now considering the kinetic energy after the masses are pulled in,

$KE_f = \frac{1}{2} * I_f * w^2_f$

The Moment of inertia would be $I_f = 3.96 \ Kg \cdot m^2$

The Angular speed would be $w_f = 2.034 \ rad/s$

Now substituting these value into the equation above

$KE_f= \frac{1}{2} *(3.96)(2.034)^2$

$= 8.192J$

8 0

3 years ago

Sara, who weighs 66 kg, is on a guilt trip after eating a 788-Calorie (788 kcal) breakfast of pancakes loaded with fruits, cream

yaroslaw [1]

Answer:

Sara must climb 10609 stairs to burn this food.

Explanation:

Chemical energy content in Sara's body = 788 kCal x 4.184 = 3296.99 kJ = 3296990 J

her body is only 25% effective in converting chemical to mechanical energy, therefore,

available mechanical energy = 25% of 3296990 = 0.25 x 3296990 = 824247.5 J --this is equivalent to the work she must do to burn this stored energy

flight of stairs = 12 cm = 0.12 m

Sara's mass m = 66 kg

Sara's weight = mg = mass x acceleration due to gravity 9.81 m/s^2

weight W = 66 x 9.81 = 647.46 N

work done = force x distance climbed d

putting in the necessary values, we have

824247.5 = 647.46 x d

d = 1273.05 m

the number of stairs Sara must climb is equal to the distance climbed divided by the height of a single stairs

number of stairs = 1273.05/0.12 = 10608.75 ≅ 10609 stairs

6 0

3 years ago

Draw a ray diagram showing how image is formed between principal focus and centre of curvature

muminat

Answer:

If the object is placed between Focus and centre of Curvature, the image forms beyond centre of curvature. If the object is placed at principal focus the image forms at infinity . If the object is placed between the pole and the principal focus, the image forms behind the mirror.

4 0

3 years ago

A group of students must conduct an experiment to determine how the location of an applied force on a classroom door affects the

Rainbow [258]

Answer:

yes

Explanation:

yea

3 0

3 years ago