Ask question

Ask question

All categories

3 years ago

12

A man wishes to row the shortest possible distance from north to south across a river which is flowing at 2 km/hr from the east.

He can row at 4 km/hr. (a) In which direction should he steer

1 answer:

sweet-ann [11.9K]3 years ago

8 0

From the diagram we have that

$sin\theta = \frac{2}{4}$

$\theta = sin^{-1} (\frac{1}{2})$

$\theta = 30\°$

Therefore the direction is 30° from east of south

You might be interested in

How long does it take (in minutes) for light to reach venus from the sun, a distance of 1.152 × 108 km?

7nadin3 [17]

Using the precise speed of light in a vacuum ( $299,792,458 \ \frac{m}{s}$ ), and your given distance of $1.152 * 10^{8} km$ , we can convert and cancel units to find the answer. The distance in m, using $\frac{1000 \ m}{1 \ km}$ , is $1.152 * 10^{11} m$ . Next, for the speed of light, we convert from s to min, using $\frac{1 \ min}{60 \ s}$ , so we divide the speed of light by 60. Finally, dividing the distance between the Sun and Venus by the speed of light in km per min, we find that it is 6.405 min.

7 0

3 years ago

The joule and the kilowatt-hour are both units of energy. 15 kw · h is equivalent to how many joules? answer in units of j.

choli [55]

The solution for the problem is:

1 Watt = 1 Joule per second
1 Watt*second = 1 Joule

a Kilowatt is 1,000 Watts
an hour is 60 seconds times 60 minutes or 3,600 seconds
a Kilowatt * hour is 1,000 Watts in 3,600 seconds

15 W*h = 15,000 Watt*hour = 15,000 Watt * 3,600 seconds = 54,000,000 Watt*second

54,000,000 Watt*second = ? Joules
54,000,000 Joules / second = 54,000,000 Watts

3 0

3 years ago

How did life evolve from nonliving matter?

Paha777 [63]

Answer: it is proposes that in Earth's prebiotic history, simple organic matter was exposed to energy in the form of volcanoes and electrical storms

Explanation:

8 0

3 years ago

A ball is thrown horizontally from the top of a building 21.8 m high. The ball strikes the ground at a point 101 m from the base

riadik2000 [5.3K]

Answer:

t=2.10 s

u= 47.40 m/s

Explanation:

given that

h= 21.8 m

x= 101 m

g=9.8 m/s²

Lets take horizontal speed of ball = u m/s

The vertical speed of the car at initial condition is zero ( v= 0).

We know that

$h=vt+\dfrac{1}{2}gt^2$

v= 0 m/s

$h=\dfrac{1}{2}gt^2$

now by putting the values

21.8 = 1/2 x 9.8 x t²

t=2.10 s

This is time when ball was in motion.

Now in horizontal direction

x = u .t

101 = u x 2.1

u= 47.40 m/s

6 0

3 years ago

A conducting loop has an area of 0.065 m2 and is positioned such that a uniform magnetic field is perpendicular to the plane of

aev [14]

Answer:

initial magnetic field 1.306 T

Explanation:

We have given area of the conducting loop $A=0.065m^2$

Emf induced = 1.2 volt

Initial magnetic field B = 0.3 T

Time dt = 0.087 sec

We know that induced emf is given by $e=\frac{d\Phi }{dt}=-A\frac{db}{dt}$

$1.2=0.065\times \frac{db}{0.087}$

$db=1.606T$

So initial magnetic field = 1.606-0.3= 1.306 T

5 0

3 years ago