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2 years ago

A motorcycle starts to move from rest. If the velocity of the motorcycle becomes 90 km/hr

Physics

1 answer:

bagirrra123 [75]2 years ago

6 0

Explanation:

90 kmhr—1 x 1000/3600 = 25ms—1

U = 0 ms—1

V = 25ms—1

t = 10 s

a = ?

a = V - U/t

a = 25 - 0/10

a = 25/10

a = 2.5 ms—1

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6. Mr. Leppold jumps out of a plane with a parachute...before the chute opens,

polet [3.4K]

1) He has both potential and kinetic energy

2) Before the parachute opens, the potential energy decreases and the kinetic energy increases

Explanation:

The gravitational potential energy of a body is the energy possessed by the object due to its position in a gravitational field, and it is given by:

$PE=mgh$

where

m is the mass of the body

g is the acceleration of gravity

h is the height of the body above the ground

On the other hand, the kinetic energy of a body is the energy possessed by the body due to its motion; it is given by

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

where

v is the speed of the object

Here Mr. Leppold has both potential and kinetic energy before opening the parachute, because:

- It is moving at a certain speed, so $v\neq 0$ , therefore he has kinetic energy

- He is at a certain height above the ground, $h\neq 0$ , therefore he has potential energy

The total mechanical energy of Mr.Leppold is the sum of the potential and the kinetic energy:

$E=PE+KE$

According to the law of conservation of energy, in absence of air resistance, this quantity remains constant.

During the fall, the height of Leppold decreases: this means that as $h$ decreases, the potential energy decreases too.

However, the total energy E must remain constant: therefore, this means that the kinetic energy KE must increase, and this occurs because the speed of Mr. Leppold increases as he falls.

Learn more about kinetic and potential energy:

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#LearnwithBrainly

8 0

3 years ago

A thin coil has 17 rectangular turns of wire. When a current of 4 A runs through the coil, there is a total flux of 5 ✕ 10−3 T ·

Alex73 [517]

Answer:

Inductance, L = 0.0212 Henries

Explanation:

It is given that,

Number of turns, N = 17

Current through the coil, I = 4 A

The total flux enclosed by the one turn of the coil, $\phi=5\times 10^{-3}\ Tm^2$

The relation between the self inductance and the magnetic flux is given by :

$L=\dfrac{N\phi}{I}$

$L=\dfrac{17\times 5\times 10^{-3}}{4}$

L = 0.0212 Henries

So, the inductance of the coil is 0.0212 Henries. Hence, this is the required solution.

7 0

3 years ago

Yashoda prepares some lime juice on a hot day. She adds 80 g of ice at a temperature of 0°C to 0.32 kg of lime juice. The temper

Vikentia [17]

Answer:

Explanation:

a )

hear energy required to melt 1 g of ice = 340 J ,

hear energy required to melt 80 g of ice = 340 x 80 J = 27220 J .

b ) energy gained by the melted ice ( water at O°C ) = m ct

where m is mass of water , s is specific heat and t is rise in temperature

= 80 x 4.2 x ( 8°C - 0°C)

= 2688 J .

c )

energy lost by lime juice = energy gained by ice and water

= 27220 J + 2688 J .

= 29908 J .

d )

Let specific heat required be S

Heat lost by lime juice = M S T

M is mass of lime juice , S is specific heat , T is decrease in temperature

= 320 g x S x ( 29 - 8 )°C

= 6720 S

For equilibrium

Heat lost = heat gained

6720 S = 29908 J

S = 4.45 J /g °C .

4 0

3 years ago

Which change would cause the largest increase in a mountain climber’s gravitational potential energy?

3241004551 [841]

<span>carrying twice the weight and climbing twice as high</span>

5 0

3 years ago

Read 2 more answers

Which statements are true concerning Newton's law of gravitation? The gravitational force is related to the mass of each object.

OLEGan [10]

Answer:

The gravitational force is related to the mass of each object.

The gravitational force is an attractive force.

Explanation:

Gravitational force is a long range force of attraction between any two masses.

Mathematically given as :

$F=G.\frac{m_1.m_2}{r^2}$

where:

$m_1 & m_2$ are the masses

r= distance between the center of mass of the two objects.

G= gravitational constant = $6.67\times 10^{-11} m^3.kg^{-1}.s^{-2}$

From the above relation of eq. (1) it is clear that,

Gravitational force is inversely proportional to the square of the distance and directly proportional to the masses.

The mass of an object is independent of its size due to the fact that density may vary for different objects.

The force of gravity varies with height as:

$\frac{g}{g_x} =(\frac{r_x}{r} )^2$

where:

$g=9.8\,m.s^{-2}$

$g_x=$ gravity at height $r_x$ of the center of mass of the object from the center of mass of the earth.

and we know that force:

$F=m\times g$

where: m= mass of the object.

5 0

3 years ago