If mechanical energy is conserved in a system the energy at any point in time can be in the form of

High blood levels of LDL cholesterol reduces your risk of developing heart

SVEN [57.7K]

Answer:

false

Explanation:

3 0

2 years ago

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A 0.950 kg block is attached to a spring with spring constant 16.0 N/m . While the block is sitting at rest, a student hits it w

Bumek [7]

Answer:

Explanation:

Given that,

Mass attached m = 0.95kg

Spring constant k = 16N/m

Instantaneous speed v = 36cm/s = 0.36m/s

Amplitude A=?

When x = 0.7A

Using conservation of energy

∆K.E + ∆P.E = 0

K.E(final) — K.E(initial) + P.E(final) — P.E(initial) = 0

At the beginning immediately the hammer hits the mass, the potential energy is 0J, Therefore, P.E(initial) = 0J, so the speed is maximum.

Also, at the end, at maximum displacement, the speed is zero, therefore, K.E(final) = 0

So, the equation becomes

— K.E(initial) + P.E(final) = 0

K.E(initial) = P.E(final)

½mv² = ½kA²

mv² = kA²

0.95 × 0.36² = 16×A²

0.12312 = 16•A²

A² = 0.12312/16

A² = 0.007695

A = √0.007695

A = 0.088 m

A = 8.8cm

B. Speed at x = 0.7A

Using the same principle above

K.E(initial) = P.E(final)

½mv² = ½kA²

Where A = 0.7A = 0.7 × 0.088 = 0.0614m

Then,

½× 0.95 × v² = ½ × 16 × 0.0614²

0.475v² = 0.0310644

v² = 0.0310644/0.475

v² = 0.0635

v = √0.0635

v = 0.252 m/s

v = 25.2 cm/s

8 0

2 years ago

Suppose a runner completes one lap around a 400-m track in a time of 50 s. Calculate the average speed of the runner.

suter [353]

Answer:

8m/s

Explanation:

Average Speed = distance / time = 400/50 = 8m/s

6 0

2 years ago

The sound wave passes from the sea-water into the air. State what happens to; the speed of the waves

dusya [7]

Answer. Explanation: Frequency of the sound decreases and the speed of sound becomes 346m/s from near about 1500 m/s.

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2 years ago

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A 100 kg box as showsn above is being pulled along the x axis by a student. the box slides across a rough surface, and its posit

Anit [1.1K]

Answer:

a) 2 m/s

b) i) $K.E = 50 (1.5t^2 + 2) ^2\\$

ii) $F = 3tm$

Explanation:

The function for distance is $x = 0.5t ^3 + 2t$

We know that:

Velocity = $v= \frac{d}{dt} x$

Acceleration = $a= \frac{d}{dt}v$

To find speed at time t = 0, we derivate the distance function:

$x = 0.5 t^3 + 2t\\v= x' = 1.5t^2 + 2$

Substitute t = 0 in velocity function:

$v = 1.5t^2 + 2\\v(0) = 1.5 (0) + 2\\v(0) = 2$

Velocity at t = 0 will be 2 m/s.

To find the function for Kinetic Energy of the box at any time, t.

$Kinetic \ Energy = \frac{1}{2} mv^2\\\\K.E = \frac{1}{2} \times 100 \times (1.5t^2 + 2) ^2\\\\K.E = 50 (1.5t^2 + 2) ^2\\$

We know that $Force = mass \times acceleration$

$a = v'(t) = 1.5t^2 + 2\\a = 3t$

$F = m \times a\\F= m \times 3t\\F = 3tm$

6 0

3 years ago