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3 years ago

If a force does a positive amount of work on an object, does the object's speed

Physics

1 answer:

Alexxandr [17]3 years ago

8 0

The speed of the object increases

Explanation:

We can answer this question by applying the work-energy theorem, which states that the work done on an object is equal to the change in kinetic energy of the object. Mathematically:

$W=K_f -K_i= \frac{1}{2}mv^2-\frac{1}{2}mu^2$

where

W is the work done on the object

$K_f, K_i$ are the final and initial kinetic energy of the object, respectively

m is the mass of the object

v is its final speed

u is its initial speed

In this case, the force does a positive amount of work on the object, so

$W>0$

This also implies that

$K_f > K_i$

And so

$\frac{1}{2}mv^2 > \frac{1}{2}mu^2$

And therefore

$v>u$

which means that the speed of the object increases.

Learn more about work:

brainly.com/question/6763771

brainly.com/question/6443626

#LearnwithBrainly

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ELEN [110]

Answer:

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Explanation:

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Ep = 1/2 x k x s²

where k = 31 N/m (spring constant)

s = 0.15 m (compression)

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When the block of mass is released, the elastic potential energy (Ep) is converted to kinetic energy (Ek). From this we can find the initial velocity of the mass of block after release

Ek = 1/2 x m x u²

where Ek = Ep = 3.4875J

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u = unknown (initial velocity)

u = 2.9526 m/s

Now that we know the initial velocity we need to find the deceleration of the mass of block due to friction. We will first find the force of friction from the following formula

F = ∪ x m x g

where F = unknown (frictional force)

∪ = 0.4 (coefficient of friction)

m = 0.08 kg (mass of block)

g = 9.81 m/s² (acceleration due to gravity)

F = 0.31392 N

From this force we calculate the deceleration based on the following formula

F = m x a

where F = 0.31392 (frictional force)

m = 0.08 kg (mass of block)

a = unknown (acceleration)

a = -3.924 m/s² -

*the negative sign is due to this value being deceleration

Now to find the total distance traveled we use the equation for motion

v² = u² + 2as

where v = 0 (final velocity)

u = 2.9526 m/s (initial velocity

a = -3.924 m/s² (deceleration due to friction)

s = unknown (distance traveled)

s = 1.11 meters

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