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2 years ago

Please help. I don’t understand this

Physics

1 answer:

skad [1K]2 years ago

5 0

The short answer is that the displacement is equal tothe area under the curve in the velocity-time graph. The region under the curve in the first 4.0 s is a triangle with height 10.0 m/s and length 4.0 s, so its area - and hence the displacement - is

1/2 • (10.0 m/s) • (4.0 s) = 20.00 m

Another way to derive this: since velocity is linear over the first 4.0 s, that means acceleration is constant. Recall that average velocity is defined as

v (ave) = ∆x / ∆t

and under constant acceleration,

v (ave) = (v (final) + v (initial)) / 2

According to the plot, with ∆t = 4.0 s, we have v (initial) = 0 and v (final) = 10.0 m/s, so

∆x / (4.0 s) = (10.0 m/s) / 2

∆x = ((4.0 s) • (10.0 m/s)) / 2

∆x = 20.00 m

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What does g-force mean?

vekshin1

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2 years ago

A runner of mass 53.0 kg runs around the edge of a horizontal turntable mounted on a vertical, frictionless axis through its cen

const2013 [10]

Answer:

0.336 rad/s

Explanation:

$\omega_1$ = Angular speed of the turntable = -0.2 rad/s

R = Radius of turntable = 2.9 m

I = Moment of inertia of turntable = $76\ kgm^2$

M = Mass of turn table = 53 kg

$v_1$ = Magnitude of the runner's velocity relative to the earth = 3.6 m/s

As the momentum in the system is conserved we have

$Mv_1R+I\omega_1=(I + MR^2)\omega_2\\\Rightarrow \omega_2=\dfrac{Mv_1R+I\omega_1}{I + MR^2}\\\Rightarrow \omega_2=\dfrac{53\times 3.6-76\times 0.2}{76+53\times 2.9^2}\\\Rightarrow \omega_2=0.336\ rad/s$

The angular velocity of the system if the runner comes to rest relative to the turntable which is the required answer is 0.336 rad/s

4 0

2 years ago

Why does a glass rod become positively charged when it is rubbed with a silk cloth?

babunello [35]

The electrons are removed from the rod and transferred to the silk cloth. This leaves the rode positively charged and the cloth negatively charged.

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2 years ago

Sarah and Kenneth are going to meet partway between their homes and each leave their home at the same time. Sarah drives at 31.0

valentina_108 [34]

Answer:

b) 105220.8 m

c) 65.38 miles

d) Kenneth's home

Explanation:

Velocity of Sarah = 31 m/s east

Velocity of Kenneth = 65 mph = 65×(1609.34/3600) m/s west

Time in seconds = 29.2×60 = 1752 s

Displacement = Velocity × time

Displacement of Sarah = 31×1752 = 54312 m

Displacement of Kenneth = 65×(1609.34/3600)×1752 = 50908.8 m

b) So, distance between their homes in meters is 54312 m + 50908.8 m = 105220.8 m

c) Converting to miles

$\frac{105220.8}{1609.34}=65.38\ miles$

Their homes are 65.38 miles apart

d) They met closer to Kenneth's house (50908.8 m)

6 0

2 years ago

A ball is thrown into the air with an initial upward velocity of 60 ft/s. Its height (h) in feet after t seconds is given by the

zavuch27 [327]

To answer the question, directly substitute the value given for t to the given function of height.
h = -16t² + 60t + 6
h = (-16)(3 s)² + (60)(3) + 6 = 42
Therefore, the height of the ball after 3 seconds is 42 ft.

4 0

2 years ago