Ask question

Ask question

All categories

7 months ago

8

Shareen finds that when she drives her motorboat upstream she can travelwith a speed of only 8 m/s, while she moves with a speed

of 12 m/s whenshe heads downstream. What is the current of the river on which Shareenis traveling?

1 answer:

ANEK [815]7 months ago

5 0

Let vb be the velocity of the motorboat and let vs be the velocity of the stream.

We know that when she drives upstream the velocity is 8 m/s, in this scenario the velocities point in opposite directions, then we have the equations:

$v_b-v_s=8$

When she drives downstream the velocites point in the same direction then we have the equation:

$v_b+v_s=12$

hence we have the system of equations:

$\begin{gathered} v_b-v_s=8 \\ v_b+v_s=12 \end{gathered}$

Solving the first equation for the velocity of the boat we have:

$v_b=8+v_s$

Plugging this in the second equation we have:

$\begin{gathered} 8+v_s+v_s=12 \\ 2v_s=4 \\ v_s=\frac{4}{2} \\ v_s=2 \end{gathered}$

Therefore, the velocity of the stream is 2 m/s

You might be interested in

A motorcycle has a constant acceleration of 3.49 m/s2. Both the velocity and acceleration of the motorcycle point in the same di

Vilka [71]

Answer:

(a)2.865 s

(b)2.865 s

Explanation:

We are given that

Acceleration,a= $3.49 m/s^2$

a.Initial speed,u=29 m/s

Final speed,v=39 m/s

We know that

$t=\frac{v-u}{a}$

Using the formula

$t=\frac{39-29}{3.49}=2.865 s$

b.Initial speed,u=59 m/s

Final speed,v=69 m/s

Again using the formula

$t=\frac{69-59}{3.49}=2.865 s$

7 0

2 years ago

An object thrown in the air has a velocity after t seconds that can be described by v(t) = -9.8t + 24 (in meters/second) and a h

marin [14]

Answer and Explanation: Kinetic energy is related to movement: it is the energy an object possesses during the movement. it is calculated as:

$K=\frac{1}{2}mv^{2}$

For the object thrown in the air:

$K=\frac{1}{2}.2.[v(t)]^{2}$

$K=(-9.8t+24)^{2}$

$K=96.04t^{2}-470.4t+576$

Kinetic energy of the object as a function of time: $K=96.04t^{2}-470.4t+576$

Potential energy is the energy an object possesses due to its position in relation to other objects. It is calculated as:

$U=mgh$

For the object thrown in the air:

$U=9.8.2.h(t)$

$U=9.8.2.(-4.9t^{2}+24t+60)$

$U=-96.04t^{2}+470.4t+1176$

Potential energy as function of time: $U=-96.04t^{2}+470.4t+1176$

Total kinetic and potential energy, also known as mechanical energy is

TME = $96.04t^{2}-470.4t+576$ + ( $-96.04t^{2}+470.4t+1176$ )

TME = 1752

The expression shows that total energy of an object thrown in the air is constant and independent of time.

6 0

2 years ago

Jared has a nut sack that weighs 14 ounces when weighed. If Becky puts an amount of force on them, x , what is the equation that

topjm [15]

X+14 bc that’s what it will equal.

6 0

2 years ago

A 100-turn, 3.0-cm-diameter coil is at rest in a horizontal plane. A uniform magnetic field 60%u2218 away from vertical increase

Xelga [282]

Answer:

Induced emf in the coil, E = 0.157 volts

Explanation:

It is given that,

Number of turns, N = 100

Diameter of the coil, d = 3 cm = 0.03 m

Radius of the coil, r = 0.015 m

A uniform magnetic field increases from 0.5 T to 2.5 T in 0.9 s.

Due to this change in magnetic field, an emf is induced in the coil which is given by :

$E=-NA\dfrac{\Delta B}{\Delta t}$

$E=-100\times \pi (0.015)^2\times \dfrac{2.5-0.5}{0.9}$

E = -0.157 volts

Minus sign shows the direction of induced emf in the coil. Hence, the induced emf in the coil is 0.157 volts.

8 0

2 years ago

Is a dog chasing its tail acceleration

AfilCa [17]

Answer:

if he is chasing his tail faster with each circle, then that would be acceleration, If not then no

7 0

1 year ago

Read 2 more answers