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2 years ago

How fast should a girl of 35 kg run so that her kinetic energy becomes 700J of?

Physics

2 answers:

Kipish [7]2 years ago

6 0

V^2 = 700J/0.5*35kg

V = square root of 40

v = 6.324 m/s

Alenkinab [10]2 years ago

6 0

Answer:

√40m/sec

Explanation:

As we know Kinetic energy = 1/2 mv^2

700 = 1/2 x 35 x v^2

1400/35 = v^2

√40 = v

So v, √40m/sec

Hope this helps you.

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A spring on a horizontal surface can be stretched and held 0.2 m from its equilibrium position with a force of 16 N. a. How much

nekit [7.7K]

Answer:

a $W_{3.5} = 490 \ J$

b $W_{2.5} = 250 \ J$

Explanation:

Generally the force constant is mathematically represented as

$k = \frac{F}{x}$

substituting values given in the question

=> $k = \frac{16}{0.2}$

=> $k = 80 \ N /m$

Generally the workdone in stretching the spring 3.5 m is mathematically represented as

$W_{3.5} = \frac{1}{2} * k * (3.5)^2$

=> $W_{3.5} = \frac{1}{2} * 80 * (3.5)^2$

=> $W_{3.5} = 490 \ J$

Generally the workdone in compressing the spring 2.5 m is mathematically represented as

$W_{2.5} = \frac{1}{2} * k * (2.5)^2$

=> $W_{2.5} = \frac{1}{2} * 80 * (2.5)^2$

=> $W_{2.5} = 250 \ J$

5 0

2 years ago

Two particles each have the same mass but particle #1 has four times the charge of particle #2. Particle #1 is accelerated from

marin [14]

Answer:

v_2 = 2*v

Explanation:

Given:

- Mass of both charges = m

- Charge 1 = Q_1

- Speed of particle 1 = v

- Charge 2 = 4*Q_1

- Potential difference p.d = 10 V

Find:

What speed does particle #2 attain?

Solution:

- The force on a charged particle in an electric field is given by:

F = Q*V / r

Where, r is the distance from one end to another.

- The Net force acting on a charge accelerates it according to the Newton's second equation of motion:

F_net = m*a

- Equate the two expressions:

a = Q*V / m*r

- The speed of the particle in an electric field is given by third kinetic equation of motion.

v_f^2 - v_i^2 = 2*a*r

Where, v_f is the final velocity,

v_i is the initial velocity = 0

v_f^2 - 0 = 2*a*r

Substitute the expression for acceleration in equation of motion:

v_f^2 = 2*(Q*V / m*r)*r

v_f^2 = 2*Q*V / m

v_f = sqrt (2*Q*V / m)

- The velocity of first particle is v:

v = sqrt (20*Q / m)

- The velocity of second particle Q = 4Q

v_2 = sqrt (20*4*Q / m)

v_2 = 2*sqrt (20*Q / m)

v_2 = 2*v

3 0

3 years ago

A 2 kg object traveling at 5 m s on a frictionless horizontal surface collides head-on with and sticks to a 3 kg object initiall

Svetlanka [38]

Answer: (d)

Explanation:

Given

Mass of object $m=2\ kg$

Speed of object $u=5\ m/s$

Mass of object at rest $M=3\ kg$

Suppose after collision, speed is v

conserving momentum

$\Rightarrow mu+0=(m+M)v\\\\\Rightarrow v=\dfrac{2\times 5}{2+3}\\\\\Rightarrow v=2\ m/s$

Initial kinetic energy

$k_1=\dfrac{1}{2}\times 2\times 5^2\\\\k_1=25\ J$

Final kinetic energy

$k_2=\dfrac{1}{2}\times (2+3)\times 2^2\\\\k_2=10\ J$

So, it is clear there is decrease in kinetic energy . Thus, energy decreases and velocity becomes 2 m/s.

4 0

2 years ago

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vladimir2022 [97]

Answer:

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5 0

2 years ago

Before designing the filter, one must understand the relationship between the output voltage of the circuit and the frequency. F

Kamila [148]

Answer:

Option b. is correct

Explanation:

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The impedances of the circuit elements depend on the frequency.

Both impedance magnitudes decrease when the frequency increases

5 0

2 years ago