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3 years ago

If a car can go from 20m/s to 40m/s in 4.0 secs, what would be it’s acceleration?

1 answer:

5 0

This is a problem that would be a good test of your understanding rather than your ability to work the formulas. 5m/s² means that the velocity increase each second is 5 m/s. So 4 s of that acceleration would increase the speed (in m/s) from 20 to 40. (Speed increase each second is 5 m/s. We need an increase of 20 m/s.)

Since the acceleration is uniform during those 4 s, we can use the simple average speed of 30 m/s. 30 m/s * 4 s = 120 m.

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A shell is fired at an angle of 35° above the horizontal at a velocity of 40 m/s. (a) What is it's speed at the highest point of

Fudgin [204]

Answer:

Part a)

$v_f = v_x = 32.77 m/s$

Part b)

T = 4.68 s

Explanation:

Part a)

Shell is fired at speed of 40 m/s at angle of 35 degree

so here we have

$v_x = 40 cos35 = 32.77 m/s$

$v_y = 40 sin35 = 22.94 m/s$

since gravity act opposite to vertical speed of the shell so at the highest point of its trajectory the vertical component of the speed will become zero

so at the highest point the speed is given

$v_f = 32.77 m/s$

Part b)

After completing the motion we know that the displacement of the object will be zero in Y direction

so we have

$\Delta y = 0$

$0 = v_y t - \frac{1}{2}gt^2$

$T = \frac{2v_y}{g}$

$T = \frac{2(22.94)}{9.81} = 4.68 s$

7 0

3 years ago

A cat walks across the kitchen with a constant speed of 0.5 m/s. How long does it take the cat to walk 8 m?

ruslelena [56]

How does the cat walk-

4 0

3 years ago

A 7.3 cm diameter loop of wire is initially oriented so that its plane is perpendicular to a magnetic field of 0.61 T pointing u

kenny6666 [7]

Answer:

induced emf = 28.65 mV

Explanation:

given data

diameter = 7.3 cm

magnetic field = 0.61

time period = 0.13 s

to find out

magnitude of the induced emf

solution

we know radius is diameter / 2

radius = 7.3 / 2

radius = 3.65 m

so induced emf is dπ/dt = Adb/dt

induced emf = A × ΔB / Δt

induced emf = πr² × ΔB / Δt

induced emf = π (0..65)² × ( 0.61 - (-0.28)) / 0.13

induced emf = 0.0286538 V

so induced emf = 28.65 mV

3 0

3 years ago

A light ray travels in the +x direction and strikes a slanted surface with an angle of 62° between its normal and the ty axis. T

Elena-2011 [213]

Answer:

- 0.6

Explanation:

Given that angle between normal y axis is 62° so angle between normal

and x axis will be 90- 62 = 28 °. Since incident ray is along x axis , 28 ° will be the angle between incident ray and normal ie it will be angle of incidence

Angle of incidence = 28 °

angle of reflection = 28°

Angle between incident ray and reflected ray = 28 + 28 = 56 °

Angle between x axis and reflected ray = 56 °

x component of reflected ray

= - cos 56 ( it will be towards - ve x axis. )

- 0.6

6 0

3 years ago

Do houses use parallels or series circuits

Vilka [71]

Every electrical outlet in your house, and every device or appliance that's
plugged into an outlet, are all in parallel. It's also most likely that all of yours
are in parallel with all the outlets, devices, and appliances in the homes or
apartments of a few of your neighbors.

The only things in your home that are connected in series are the switches
that turn things on and off.

3 0

3 years ago

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