1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Olegator [25]
3 years ago
8

A child in danger of drowning in a river is being carried downstream by a current that flows due south uniformly with a speed of

3 km/hr. the child is 0.5 km from the shore and 2 km north (i.e., upstream) of a boat landing when a rescue boat sets out.a) if the boat proceeds at its maximum speed of 24 km/hr with respect to the water, what angle relative to north should the pilot point the bow of the boat in order to reach the child in the minimum amount of time? please enter your answer in degrees.angle james walker
Physics
1 answer:
tia_tia [17]3 years ago
3 0

Let the rescue boat starts at an angle theta with the North

now its velocity towards East is given as

v_x = 24sin\theta

v_y = -24cos\theta + 3

now in some time "t" it will catch the boy

so we will have

t = \frac{0.5}{24sin\theta}

also we have

t = \frac{2}{-24cos\theta + 3}

now we have

\frac{2}{-24cos\theta + 3} = \frac{0.5}{24sin\theta}

4*24sin\theta = - 24cos\theta + 3

96 sin\theta + 24cos\theta = 3

by solving above we got

\theta = 164 degree

You might be interested in
The size (radius) of an oxygen molecule is about 2.0 ×10−10 m. Make a rough estimate of the pressure at which the finite volume
timurjin [86]

Answer:

P = 1 x 10⁸ Pa

Explanation:

given,

radius = 2.0 ×10⁻¹⁰ m

Temperature

T = 300 K

Volume of gas molecule =

V = \dfrac{4}{3}\pi r^3

V = \dfrac{4}{3}\pi (2\times 10^{-10})^3

 V = 33.51 x 10⁻³⁰ m³

we know,

P  V = 1 . k T

k = 1.38  x 10⁻²³ J/K

P(33.51 x 10⁻³⁰) = 1 . (1.38  x 10⁻²³) x 300

P = 1.235 x 10⁸ Pa

for 1 significant figure

P = 1 x 10⁸ Pa

6 0
3 years ago
Give examples of not useful high friction
Tatiana [17]
Friction can be bad by being too strong or too weak. 

<span>Sometimes, when it is too strong, it decreases efficiency since some energy is wasted and turns to heat. Friction can also d</span><span>amage equipment/objects like when you slide it on the floor.
</span>
When friction is too weak, like for instance when there is black ice- our center of gravity is displaced too quickly and we can fall. Likewise, if there is a lot of slush on the ground, cars can slip and slide.
6 0
3 years ago
2. If the efficiency of a device is 64 %, what is the amount of Energy lost/ wasted by this device?
Inessa05 [86]
It would be 78 becuase the 2 percent of 64 is many of energy lost
3 0
3 years ago
A large flat block of mass 7 m rests on a level, smooth tabletop (µk ≈ 0). On top of it is a much smaller block of mass m, with
mariarad [96]

Answer:

3. µs g /7

Explanation:

The largest Force appear when the maximal friction Force is required.

Second Newton law for the small block:

F_friction=u_s*N=u_s*(mg)

F-F_friction=ma

F-u_s*(mg)=ma

Second Newton law for the Big Block:

F_friction=7ma

u_s*(mg)=7ma

a=u_s*g/7

8 0
3 years ago
The answer and how to do it?? Thanks
denis-greek [22]

Answer:

14 m/s²

Explanation:

Start with Newton's 2nd law: Fnet=ma, with F being force, m being mass, and a being acceleration. The applied forces on the left and right side of the block are equivalent, so they cancel out and are negligible. That way, you only have to worry about the y direction. Don't forget the force that gravity has the object. It appears to me that the object is falling, so there would be an additional force from going down from weight of the object. Weight is gravity (can be rounded to 10) x mass. Substitute 4N+weight in for Fnet and 1kg in for m.

(4N + 10 x 1kg)=(1kg)a

14/1=14, so the acceleration is 14 m/s²

4 0
3 years ago
Other questions:
  • A particle moves in a straight line with an initial velocity of 37 m/s and a constant acceleration of 20 m/s2. If at t = 0, x =
    9·1 answer
  • What is the maximum weight a boat can hold if a boat can displace 60.5ml?
    6·1 answer
  • The mass of the earth is 6x10^24 kg and its radius is 6400 km.What is the mass of a man weighing 977 N in a spring balance.​
    7·1 answer
  • An adiabatic nozzle has an inlet area of 1 m^2 and an outlet area of 0.25 m^2. Water enters the nozzle at a rate of 5 m^3/s and
    12·1 answer
  • Why are experiments often performed in laboratories?
    10·1 answer
  • A 4 kg block has a coefficient of friction of 0.3 between itself and the surface
    9·1 answer
  • Models are frequently used in science to assist in the understanding of complex information. Models can include items like a wor
    7·1 answer
  • A 12 kg<br> mass is lifted to a height of 2 m. What is its potential energy<br> at this position?
    5·2 answers
  • 1. In the context of the poem, what does it mean to feel alone? How can two people experience isolation despite living in the sa
    12·1 answer
  • How dose nail polish burnt in water?
    7·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!