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4 years ago

1. Explain the importance of doing muscular strength and muscular endurance activities.

2 answers:

8 0

Because just lifting heavy weights is tearing down your muscles and so doing an insurance workout lets your muscles come back bigger and stronger.

Maurinko [17]4 years ago

3 0

It builds your muscles, strengthens your flexibility, keeps you in shape, gets your blood moving in your body, etc.

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A student drops an object from rest above a force plate that records information about the force exerted on the object as a func

OLEGan [10]

Answer:

A. The mass of the object

Explanation:

p = mv

p = momentum

m = mass

v = velocity

5 0

3 years ago

Read 2 more answers

SOUND IS A FORM OF WAVE.LIST AT LEAST 3 REASONS TO SUPPORT IDEA THAT SOUND IS A WAVE.

algol [13]

1 The question asks for a certain quantity of examples in a list (Name 6 factors that contributed to the start of World War I, What 3 subatomic particles constitute an atom? etc).
2 The question is academically precise and, therefore, indecisive in the wording (What are the 2 kinds of loading most professional engineers and academics in the field of engineering today generally consider to be relevant in most cases when considering typical types of structure usually made of common materials using well-understand methods?)
3 The question challenges the answerer to defend a position as opposed to merely rattling off a list based on knowledge alone, thereby invoking higher levels of Bloom's Taxonomy. (What are 4 arguments that could be used to defend arguments made by the physicists of the day that electromagnetic waves must move through an illusive substance called 'the ether?)

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3 years ago

If you started the motor of a boat in the middle of a lake, who would detect the sound of the motor first: a friend sitting on t

ArbitrLikvidat [17]

Answer:

A friend snorkeling just below the surface of the water along the same shore will detect the sound first.

Explanation:

The speed of sound in water medium is faster than that through the air.
Sound propagates through the medium by transferring through the molecules on it. Water has more closely packed molecules due to which the speed is faster.
In fact, the sound's speed in water is almost four times faster than that in the air.
So the guy in the water surface gets to hear sound faster than the one in sore.

6 0

4 years ago

Read 2 more answers

FIGURE 2 shows a 1.5 kg block is hung by a light string which is wound around a smooth pulley of radius 20 cm. The moment of ine

Sindrei [870]

Answer:

At t = 4.2 s

Angular velocity: 6. 17 rad /s

The number of revolutions: 2.06

Explanation:

First, we consider all the forces acting on the pulley.

There is only one force acting on the pulley, and that is due to the 1.5 kg mass attached to it.

Therefore, the torque on the pulley is

$\tau=Fd=mg\cdot R$

where m is the mass of the block, g is the acceleration due to gravity, and R is the radius of the pulley.

Now we also know that the torque is related to angular acceleration α by

$\tau=I\alpha$

therefore, equating this to the above equation gives

$mg\cdot R=I\alpha$

solving for alpha gives

$\alpha=\frac{mgR}{I}$

Now putting in m = 1.5 kg, g = 9.8 m/s^2, R = 20 cm = 0.20 m, and I = 2 kg m^2 gives

$\alpha=\frac{1.5\cdot9.8\cdot0.20}{2}$ $\boxed{\alpha=1.47s^{-2}}$

Now that we have the value of the angular acceleration in hand, we can use the kinematics equations for the rotational motion to find the angular velocity and the number of revolutions at t = 4.2 s.

The first kinematic equation we use is

$\theta=\theta_0+\omega_0t+\frac{1}{2}\alpha t^2$

since the pulley starts from rest ω0 = 0 and theta = 0; therefore, we have

$\theta=\frac{1}{2}\alpha t^2$

Therefore, ar t = 4.2 s, the above gives

$\theta=\frac{1}{2}(1.47)(4.2)^2$

$\boxed{\theta=12.97}$

So how many revolutions is this?

To find out we just divide by 2 pi:

$\#\text{rev}=\frac{\theta}{2\pi}=\frac{12.97}{2\pi}$ $\boxed{\#\text{rev}=2.06}$

Or about 2 revolutions.

Now to find the angular velocity at t = 4.2 s, we use another rotational kinematics equation:

$\omega^2=w^2_0+2\alpha(\Delta\theta)_{}$

Since the pulley starts from rest, ω0 = 0. The change in angle Δθ we calculated above is 12.97. The value of alpha we already know to be 1.47; therefore, the above becomes: