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4 years ago

Question

Physics

1 answer:

lana [24]4 years ago

3 0

26,000 years is approximately how long it takes for the earths revolution to change

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A rack of seven spherical bolwing balls (each 7.00 kg, radius of 9.50 cm) is positioned along a line located a distance =0.850 m

lapo4ka [179]

Answer:

8.72* $10^{-12}$ N

Explanation:

force of attraction f = G m1m2/ r^2 = $\frac{6.67*10^{-11}*7*5*2.70 }{.85*.85*1000}$ = 8.72* $10^{-12}$ N

4 0

3 years ago

A heavy boy and a lightweight girl are balanced on a massless seesaw. The boy moves backward, increasing his distance from the p

slava [35]

Answer:

b. The side the boy is sitting on will tilt downward

Explanation:

Initially, the seesaw is balanced because the torque exerted by the boy is equal to the torque exerted by the girl:

$\tau_b = \tau_g\\W_b d_b = W_g d_g$

where

Wb is the weight of the boy

db is the distance of the boy from the pivot

Wg is the weight of the girl

dg is the distance of the girl from the pivot

When the boy moves backward, the distance of the boy from the pivot ( $(d_b)$ increases, therefore the torques are no longer balanced: the torque exerted by the boy will be larger, and therefore the side of the boy will tilt downward.

5 0

3 years ago

Which refers to the amount of heat required to change the temperature of 1 gram of a substance by 1°C and is related to the chem

timama [110]

Answer:

Specific heat

Explanation:

8 0

3 years ago

To find the number of neurons in an atom you would subtract

Marianna [84]

you can subtract the atomic number from the mass number to find the number of neutrons.

3 0

3 years ago

Read 2 more answers

Two astronauts (each with mass 100 kg) are drifting together through space. They are connected to each other by a rope 5 m in le

Nana76 [90]

Answer:

1000 kgm²/s, 400 J

1000 kgm²/s, 1000 J

600 J

Explanation:

m = Mass of astronauts = 100 kg

d = Diameter

r = Radius = $\frac{d}{2}$

v = Velocity of astronauts = 2 m/s

Angular momentum of the system is given by

$L=mvr+mvr\\\Rightarrow L=2mvr\\\Rightarrow L=2\times 100\times 2\times 2.5\\\Rightarrow L=1000\ kgm^2/s$

The angular momentum of the system is 1000 kgm²/s

Rotational energy is given by

$K=I\omega^2\\\Rightarrow K=\frac{1}{2}(mr^2)\left(\frac{v}{r}\right)^2\\\Rightarrow K=mv^2\\\Rightarrow K=100\times 2^2\\\Rightarrow K=400\ J$

The rotational energy of the system is 400 J

There no external toque present so the initial and final angular momentum will be equal to the initial angular momentum 1000 kgm²/s

$L_i=L_f\\\Rightarrow 2mv_ir_i=2mv_fr_f\\\Rightarrow v_f=\frac{v_ir_i}{r_f}\\\Rightarrow v_f=\frac{2\times 2.5}{0.5}\\\Rightarrow v_f=10\ m/s$

Energy

$E_2=mv_f^2\\\Rightarrow E_2=100\times 10\\\Rightarrow E_2=1000\ J$

The new energy will be 1000 J

Work done will be the change in the kinetic energy

$W=E_2-E\\\Rightarrow W=1000-400\\\Rightarrow W=600\ J$

The work done is 600 J

5 0

3 years ago