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3 years ago

Cheetahs are the fastest land animals and have been clocked at speeds up to 70 mph. What is the speed in m/s?

Physics

2 answers:

White raven [17]3 years ago

4 0

Answer: 31.3m/s

Explanation:

Fed [463]3 years ago

3 0

Answer:

That's 31. 1 m/s for you

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Jill does twice as much work as Jack does and in half the time. Jill's power output is Group of answer choices one-fourth as muc

Musya8 [376]

Answer:

Second Choice.

Explanation:

Jack's Power = W/t

Jill's Power = 2W/(0.5)*t

2/0.5 = 4

Jill's Power = 4*W/t

Jill's Power is 4 times greater than Jack's

Second Choice

3 0

2 years ago

A4 40 kg girl skates at 3.5 m/s one ice toward her 65 kg friend who is standing still, with open arms. As they collide and hold

salantis [7]

Explanation:

Below is an attachment containing the solution.

8 0

3 years ago

A woman with a mass of 52.0 kg is standing on the rim of a large disk that is rotating at an angular velocity of 0.470 rev/s abo

Charra [1.4K]

Explanation:

It is given that,

Mass of the woman, m₁ = 52 kg

Angular velocity, $\omega=0.47\ rev/s=2.95\ rad/s$

Mass of disk, m₂ = 118 kg

Radius of the disk, r = 3.9 m

The moment of inertia of woman which is standing at the rim of a large disk is :

$I={m_1r^2}$

$I={52\times 3.9^2}$

I₁ = 790.92 kg-m²

The moment of inertia of of the disk about an axis through its center is given by :

$I_2=\dfrac{m_2r^2}{2}$

$I_2=\dfrac{118\times (3.9)^2}{2}$

I₂ =897.39 kg-m²

Total moment of inertia of the system is given by :

$I=I_1+I_2$

$I=790.92+897.39$

I = 1688.31 kg-m²

The angular momentum of the system is :

$L=I\times \omega$

$L=1688.31 \times 2.95$

$L=4980.5\ kg-m^2/s$

So, the total angular momentum of the system is 4980.5 kg-m²/s. Hence, this is the required solution.

8 0

3 years ago

The muzzle velocity of a rifle bullet is 709 m s−1along the direction of motion. If the bullet weighs 35 g, and the uncertainty

nydimaria [60]

Answer:

Uncertainty in position of the bullet is $\Delta x=1.07\times 10^{-33}\ m$

Explanation:

It is given that,

Mass of the bullet, m = 35 g = 0.035 kg

Velocity of bullet, v = 709 m/s

The uncertainty in momentum is 0.20%. The momentum of the bullet is given by :

$p=mv$

$p=0.035\times 709=24.81\ kg-m/s$

Uncertainty in momentum is,

$\Delta p=0.2\%\ of\ 24.81$

$\Delta p=0.049$

We need to find the uncertainty in position. It can be calculated using Heisenberg uncertainty principal as :

$\Delta p.\Delta x\geq \dfrac{h}{4\pi}$

$\Delta x=\dfrac{h}{4\pi \Delta p}$

$\Delta x=\dfrac{6.62\times 10^{-34}}{4\pi \times 0.049}$

$\Delta x=1.07\times 10^{-33}\ m$

Hence, this is the required solution.

7 0

3 years ago

A 0.49 m copper rod with a mass of 0.15 kg carries a current of 13 A in the positive y direction. Let upward be the positive dir

Helen [10]

Answer:

Magnetic field, B = 0.23 T

Explanation:

Given that,

Length of the copper rod, L = 0.49 m

Mass of the copper rod, m = 0.15 kg

Current in rod, I = 13 A (in +ve y direction)

When the rod is placed in magnetic field, the magnetic force is balanced by its weight such that :

$BIL=mg\\\\B=\dfrac{mg}{IL}\\\\B=\dfrac{0.15\times 9.8}{13\times 0.49}\\\\B=0.23\ T$

So, the magnitude of the minimum magnetic field needed to levitate the rod is 0.23 T.

6 0

3 years ago