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3 years ago

James accelerates his skate board uniformly along a straight road from rest to 10 m/s in 4 seconds. What is James Acceleration?

Physics

1 answer:

lawyer [7]3 years ago

4 0

Given:

u(initial velocity)=0

v(final velocity)= 10 m/s

t= 4 sec

Now we know that

v= u + at

Where v is the final velocity

u is the initial velocity

a is the acceleration measured in m/s^2

t is the time measured in sec

10=0+ax4

a=10/4

a=2.5 m/s^2

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Jumping up before the elevator hits. After the cable snaps and the safety system fails, an elevator cab free-falls from a height

butalik [34]

Answer:

a) I = -2257.6 Kg*m/s

b) F = -451,520N

Explanation:

part a.

we know that:

I = $P_f-P_i$

where I is the impulse, $P_f$ the final momentum and $P_i$ the initial momentum.

so:

I = $MV_f-MV_i$

where M is the mass, $V_f$ the final velocity and $V_i$ the initial velocity.

Therefore, we have to find the initial velocity or the velocity of the passenger just before the collition.

now, we will use the law of the conservation of energy:

$E_i=E_f$

so:

mgh = $\frac{1}{2}MV_i^2$

where g is the gravity and h the altitude. So, replacing values, we get:

(85kg)(9.8m/s^2)(36m)= $\frac{1}{2}(85kg)V_i^2$

solving for $V_i$ :

$V_i = 26.56m/s$

Then, replacing in the initial equation:

I = $MV_f-MV_i$

I = $(85kg)(0m/s)-(85kg)(26.56m/s)$

I = -2257.6 Kg*m/s

Then, the impulse is -2257.6 Kg*m/s, it is negative because it is upwards.

part b.

we know that:

Ft = I

where F is the average force, t is the time and I is the impulse. So, replacing values, we get:

F(0,005s) = -2257.6 Kg*m/s

solving for F:

F = -451520N

Finally, the force is -451,520N, it is negative because it is upwards.

3 0

3 years ago

A boy pulls his toy on a smooth horizontal surface with a rope inclined at 60 degrees to the horizontal. If the effective force

lana66690 [7]

I'm thinking that you're supposed to divide. So you would divide 5 into 60 and get 12

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3 years ago

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A circular window of 30 cm diameter in a submarine can withstand a maximum force of 5.20 × 105 N. The maximum depth in a lake to

Svetach [21]

Answer: Option (b) is the correct answer.

Explanation:

The given data is as follows.

F = $5.20 \times 10^{5}$ N

g = 9.8 m/s

radius = $\frac{diameter}{2}$

= $\frac{30 cm}{2}$ = 15 cm = 0.15 m (as 1 m = 100 cm)

Formula to calculate depth is as follows.

F = $\rho \times g \times h \times A$

or, h = $\frac{F}{\rho \times g \times A}$

h = $\frac{5.2 \times 10^{5}}{1000 \times 9.8 \times (3.1416 \times (0.15 m^{2})}$

= 751 m

Thus, we can conclude that the maximum depth in a lake to which the submarine can go without damaging the window is closest 750 m.

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3 years ago

Decay of ______ waste present in waste water leads to unpleasant smell

victus00 [196]

Decay of Schizomycetes waste present in waste water leads to unpleasant smell.

These microorganisms, known as iron and sulfur bacteria, cause hydrogen sulfide to be found in water supplies. They include crenothrix and beggiatoa. Most often found in groundwater supplies, they produce an offensive odor of decaying matter. (I'm not sure)

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3 years ago

It has been known for many years that ceramics can conduct electricity. In 2008, scientists found a ceramic material that can co

ollegr [7]

Answer:

The answer is the second option.

Explanation:

This is a higher temperature than Onnes's experiment, and it will allow for a broader use of superconductors.

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3 years ago

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