All categories

3 years ago

HELP Please Hurry

Physics

2 answers:

nlexa [21]3 years ago

6 0

The correct answers are:

A plane landing on an aircraft carrier.

Rain sticking to a window.

Two train cars coupling together.

2. The total momentum is zero.

3. 3.6 (kg*m/s) (Option C)

Explanations:

1) In simple terms (not a textbook definition), perfectly inelastic collision is a collision in which two bodies stick together (or becomes one) after a collision. Now let us have a look at the options:

A baseball bouncing off a bat: After collision, the ball and the bat do not stick to one another; therefore, it is NOT a perfectly inelastic collision.

Bumper cars bumping off of each other: After collision, cars bump off of each other, making their collision elastic, not perfectly inelastic collision.

A cue ball hitting an eight ball and stopping: After collision, although the cue ball stops, but all of its momentum will be transferred to the eight ball; and eight ball will start moving, where is cue ball stops. Not a perfectly inelastic collision.

A plane landing on an aircraft carrier: After plan lands, the plane and the aircraft carrier will be incontent with each other; making their collision perfectly inelastic.

Rain sticking to a window: Rain drop sticking to a window means both stick together after a collision, making it a perfectly inelastic collision.

Two train cars coupling together: Again both cars are sticking together, making it a perfectly inelastic collision.

Hence the correct answers are:

A plane landing on an aircraft carrier.

Rain sticking to a window.

Two train cars coupling together

7) Always remember that in a closed system, the total momentum is conserved, meaning:

Total initial momentum = Total final momentum

Initially, bodies are at rest, the total initial momentum (mv) is zero (since (m+2m)*0 = 0; as v = 0). As it is the closed system, the total final momentum will be equal to the total initial momentum. As the total initial momentum is zero, the total final momentum will also be zero.

Hence the correct answer is: The total momentum is zero.

3) As you can see in the table, the initial momentum of each and every entry is equal to the final momentum. In the case of X, as the final momentum is 3.6 kg*m/s, the initial momentum will be same as the final momentum (by considering the pattern in the table); therefore X (the initial momentum) will be 3.6 kg*m/s.

Hence the correct answer is: X = 3.6 (Option C)

Mandarinka [93]3 years ago

3 0

Answer:

A plane landing on an aircraft carrier.

Rain sticking to a window.

Two train cars coupling together.

Explanation:

In perfectly inelastic collision when two objects collide each other then after collision they stick with each other as in this type of collision there is no separation after collision.

so here we have to choose such cases in the given all options

A plane landing on an aircraft carrier:

After landing the aircraft is in always contact with the ground so it is satisfying the condition of inelastic collision.

Rain sticking to a window:

Rain drops sticking to the window after it collide with it so it is the condition of perfect inelastic collision.

Two train cars coupling together:

Two cars collide and stick with each other so this is the condition of perfect inelastic collision.

Answer:

The total momentum is zero.

Explanation:

As we know that it is a type of perfect inelastic collision so here we can use momentum conservation as there is no external force on it.

Since we know that if net external force on a system is zero then momentum of the system is always conserved.

So in this case both the masses are at rest initially so initial momentum is zero here so at all instants of time final momentum is also zero.

so total momentum is zero

Answer:

Option C 3.6 (kg*m/s)

Explanation:

Since here in all cases we can see that it is following the condition of momentum conservation

Here by momentum conservation we can say that

initial momentum = final momentum

so from given table we know that

final momentum = 3.6 kg m/s

so initial momentum must be same

so value of x = 3.6 kg m/s

You might be interested in

When the voltage and current have _____ polarities in a pure capacitive circuit, the capacitor is discharging and the energy is

tangare [24]

Answer:opposite

Explanation:for a capacitor to discharge (after charging) the polarities of the current and voltage have to be reversed

6 0

3 years ago

Object A has 27 J of kinetic energy. Object B has one-quarter the mass of object A.

andreev551 [17]

Answer:

the final speed of object A changed by a factor of $\frac{1}{\sqrt{3} }$ = 0.58

the final speed of object B changed by a factor of $\sqrt{\frac{5}{3} }$ = 1.29

Explanation:

Given;

kinetic energy of object A, = 27 J

let the mass of object A = $m_A$

then, the mass of object B = $m_B = \frac{m_A}{4}$

work done on object A = -18 J

work done on object B = -18 J

let $v_i$ be the initial speed

let $v_f$ be the final speed

For object A;

$K.E_A = 27\\\\\frac{1}{2} m_A v_i^2 = 27\\\\m_A v_i^2 = 54\\\\m_A = \frac{54}{v_i^2} ----Equation \ (1)\\\\Apply \ work-energy \ theorem;\\\\\delta K.E_A = -18\\\\\frac{1}{2} m_A v_f^2 - \frac{1}{2} m_A v_i^2 = -18\\\\\frac{1}{2} m_A ( v_f^2 \ - v_i^2 )\ =- 18\\\\v_f^2 \ - v_i^2 = -\frac{36}{m_A} ---Equation \ (2)\\\\v_f^2 \ - v_i^2 = -\frac{36v_i^2}{54}\\\\ v_f^2 \ =v_i^2 - \frac{36v_i^2}{54}\\\\ v_f^2 = \frac{54v_i^2 -36v_i^2 }{54} \\\\v_f^2 = \frac{18v_i^2}{54} \\\\v_f^2 = \frac{v_i^2}{3} \\\\$

$v_f = \sqrt{\frac{v_i^2}{3} }\\\\v_f = \frac{1}{\sqrt{3} } \ v_i\\\\$

Thus, the final speed of object A changed by a factor of $\frac{1}{\sqrt{3} }$ = 0.58

To obtain the change in the final speed of object B, apply the following equations.

$K.E_B_i = \frac{1}{2} m_Bv_i^2\\\\m_B = \frac{m_A}{4} \\\\K.E_B_i = \frac{1}{2}(\frac{m_A}{4} )v_i^2\\\\K.E_B_i = \frac{m_Av_i^2}{8} \\\\But, \ m_Av_i^2 = 54 \\\\K.E_B_i = \frac{54}{8} \\\\Apply \ work-energy \ theorem ;\\\\\delta K.E = -18\\\\K.E_f -K.E_i = -18\\\\\frac{1}{2}m_Bv_f^2 - \frac{1}{2} m_Bv_i^2 = -18\\\\Recall \ m_B = \frac{m_A}{4} \\\\\frac{1}{2}(\frac{m_A}{4} )v_f^2 - \frac{1}{2}(\frac{m_A}{4} )v_i^2 = -18\\\\\frac{1}{2}\times \frac{m_A}{4} (v_i^2 -v_f^2) = 18\\\\$

$\frac{1}{2}\times \frac{m_A}{4} (v_i^2 -v_f^2) = 18\\\\v_i^2 -v_f^2 = \frac{8}{m_A} \times 18\\\\v_i^2 -v_f^2 =\frac{144}{m_A} \\\\But , m_A = \frac{54}{v_i^2} \\\\v_i^2 -v_f^2 =\frac{144v_i^2}{54} \\\\v_f^2 = v_i^2 - \frac{144v_i^2}{54}\\\\v_f^2 = \frac{54v_i^2-144v_i^2}{54}\\\\ v_f^2 = \frac{-90v_i^2}{54} \\\\v_f^2 = \frac{-5v_i^2}{3} \\\\|v_f| = \sqrt{\frac{5v_i^2}{3}} \\\\|v_f| = \sqrt{\frac{5}{3}} \ v_i$

Thus, the final speed of object B changed by a factor of $\sqrt{\frac{5}{3} }$ = 1.29

3 0

3 years ago

The height of a circular tower is 179 meters and its diameter is 48 meters. (Assume that the building is a perfect cylinder). Wh

EastWind [94]

The definition of a scale of 1: 166 will mean that the scale of 1 in the model will be equivalent to 166 times the measurement in the real model, therefore we will have that the height would be 166 times smaller than the 179m given:

$h = \frac{179m}{166} = 1.078m = 107.8cm$