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11111nata11111 [884]

2 years ago

15

"A boat that can travel at 4.0 km/h in still water crosses a river with a current of 2.0 km/h. At what angle must the boat be po

inted upstream (that is, relative to its actual path) to go straight across the river?

1 answer:

IRISSAK [1]2 years ago

8 0

Answer:

30 degrees

Explanation:

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A cannon fires a cannonball 500.0 m downrange when set at a 45.0o angle. At what velocity does the cannonball leave the cannon?

kobusy [5.1K]

Answer:

v = 70 m/s

Explanation:

Range on the cannon ball is given as

$d = 500.0 m$

here the angle of the projection of the ball is given as 45 degree

now we know that if the velocity of the ball is "v" then its two components will be given as

$v_x = vcos45$

$v_y = vsin45$

so here time of flight of the motion is given as

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

$T = \frac{2vsin45}{g}$

also the range is given as

$R = v_x T$

$R = (vcos45)(\frac{2vsin45}{g})$

now plug in all data in this equation

$500.0 = \frac{v^2(2sin45cos45)}{g}$

$v = 70 m/s$

4 0

3 years ago

Why is gravity so weird? Will mark as brainliest

QveST [7]

Answer:

No force is more familiar than gravity — it’s what keeps our feet on the ground, after all. And Einstein’s theory of general relativity gives a mathematical formulation for gravity, describing it as a “warping” of space.

Explanation:

7 0

3 years ago

Read 2 more answers

Inertia is responsible for :

trasher [3.6K]

<span>b. the reason we must wear seat belts </span>

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3 years ago

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A fixed coil of wire with 10 turns and an area of 0.055 m2 is placed in a perpendicular magnetic field. This field oscillates in

Blababa [14]

Answer:

Part a)

Average EMF for half cycle is

$E_{avg} = 2.64 V$

Part b)

For one complete cycle we will have

$E_{avg} = 0$

Part c)

Maximum induced EMF will be at

t = 0.025 s and 0.075 s

minimum induced EMF is at

t = 0.05s and 0.1 s

Explanation:

As we know that magnetic field is oscillating in direction as well as magnitude

so induced EMF is given as

$E = NBA\omega sin(\omega t)$

Part a)

For average value of EMF from positive maximum to negative maximum which is equal to half cycle

so we have

$E_{avg} = NBA\omega \frac{2}{T}\int_0^{T/2} sin(\omega t) dt$

$E_{avg} = \frac{2NBA\omega}{\pi}$

$E_{avg} = \frac{2(10)(0.12)(0.055)(2\pi (10))}{\pi}$

$E_{avg} = 2.64 V$

Part b)

For one complete cycle we will have

$E_{avg} = NBA\omega \frac{1}{T}\int_0^T sin(\omega t) dt$

$E_{avg} = 0$

Part c)

Maximum induced EMF will be at

$t = \frac{T}{4} and \frac{3T}{4}$

here we know

$T = \frac{1}{f} = 0.1 s$

t = 0.025 s and 0.075 s

minimum induced EMF is at

$t = \frac{T}{2} and T$

so it is

t = 0.05s and 0.1 s

8 0

3 years ago

a 15kg television sits on a shelf at a height of 0.3 m how much gravitational potential energy is added to the television when i

DedPeter [7]

Answer:

<h2>103 Joules</h2>

Explanation:

In this problem we are required to find the potential energy possessed by the television

Given data

mass of television m = 15 kg

height added above the ground, h= 1-0.3 = 0.7 m

acceleration due to gravity g = 9.81 m/s^2

apply the formula for potential energy we have

P.E= m*g*h

P.E = 15*9.81*0.7 = 103 Joules

7 0

2 years ago