A 5,000 kg truck moving at 8 m/s has the same momentum as a 2,500 kg car. What is the velocity of

A 400.0-m-wide river flows from west to east at 30.0 m/min. Your boat moves at 100.0 m/min relative to the water no matter which

Ratling [72]

Answer:

a. boat would drift towards a NE direction

b. 104.4m/min * t

c. false

d. point downstream of c, -79.19 deg NE

e. 3.898mins

f. 389.8m

Explanation:

a. downstream is a location with respect to the direction of the flow of the river, in this case from west to east. the boat would drift towards the NE direction due to the direction of water current.

b. lets say it takes time t to travel across the river, the resultant speed of boat would be given as Rs= sqrt ( 100/min^2 + 30m/mins^2) = 104.4m/mins

distance traveled would be 104.4 *t

c. false, the direction of boat wouldnt remain perpendicular the entire crossing but would drift toward the NE bearing provided the driver doesnt change or steer the boat.

d. a. taking the definition of downstream in question (a), your boat would land at a point x downstream to c

b. to land at c boat must be inclined at an angle of -79.19 deg NE, given by using the width of river and the distance of b to c.

cosФ= 75/ 400

Ф= 79.19°NE to get to c you must position boat at an angle of -79.19 deg from your initial bearing.

e. speed = distance/ time, time = distance / speed.

aiming toward point c, speed of boat is the resultant speed of boat with respect to the speed of water, using Pythagoras also

speed= $\sqrt{ 100^{2} + 30^{2} }$ = 104m/mins

distance to move from point a to c is given also given by

distance = $\sqrt{400^{2} + 75^{2} }$ = 406.97m

time = 406.97/ 104.4 = 3.89mins...

f. on the ground the observer see the boat speed as 100m/min.

distance traveled is given by speed * time= 100 * 3.89= 389m

g. speed of boat observed would be 100m/min

5 0

2 years ago

How are speed and velocity different?

liubo4ka [24]

Velocity tells you how fast and in what direction. Speed only tells how fast.

4 0

3 years ago

Read 2 more answers

An electron moves in a circular path perpendicular to a uniform magnetic field with a magnitude of 2.14 mT. If the speed of the

JulsSmile [24]

Answer:

(a) 3.9cm

(b) 1.66 x 10⁻⁸s

Explanation:

Since the electron is moving in a circular path, the centripetal acceleration needed to keep it from slipping off is provided by the magnetic force. This force (F), according to Newton's second law of motion is given by,

F = m x a --------------(i)

Where;

m = mass of the particle

a = acceleration of the mass

The centripetal acceleration is given by;

a = v² / r [v = linear velocity of particle, r = radius of circular path]

<em>Therefore, equation (i) becomes;</em>

F = m v²/ r --------------------(ii)

The magnitude of the magnetic force on a moving charge in a magnetic field as stated by Lorentz's law is given by;

F = qvBsinθ -------------(iii)

Where;

q = charge of the particle

v = velocity of the particle

B = magnetic field

θ = angle between the velocity and the magnetic field

<em>Combine equations (ii) and (iii) as follows;</em>

m (v² / r) = qvBsinθ [divide both side by v]

m v / r = qBsinθ [make r subject of the formula]

r = (m v) / (qBsinθ) ---------(iv)

(a) From the question;

v = 1.48 x 10⁷m/s

B = 2.14mT = 2.14 x 10⁻³T

θ = 90° [since the direction of velocity is perpendicular to magnetic field]

m = mass of electron = 9.11 x 10⁻³¹kg

q = charge of electron = 1.6 x 10⁻¹⁹C

Substitute these values into equation (iv) as follows;

r = (9.11 x 10⁻³¹ x 1.48 x 10⁷) / (1.6 x 10⁻¹⁹ x 2.14 x 10⁻³ sin 90°)

r = 3.9 x 10⁻²m

r = 3.9cm

Therefore, the radius of the circular path is 3.9cm

(b) The time interval required to complete one revolution is the period (T) of the motion of the electron and it is given by

T = d / v --------------(*)

Where;

d = distance traveled in the circular path in one complete turn = 2πr

v = velocity of the motion = 1.48 x 10⁷m/s

d = 2 π (3.9 x 10⁻²) [Take π = 22/7 = 3.142]

d = 2(3.142)(3.9 x 10⁻²) = 0.245m

Substitute the values of d and v into equation (*) as follows;

T = 0.245 / 1.48 x 10⁷

T = 0.166 x 10⁻⁷s

T = 1.66 x 10⁻⁸s

Therefore, the time interval is 1.66 x 10⁻⁸s

6 0

3 years ago

"One of the main projects being carried out by the Hubble Space Telescope is to measure the distances of galaxies located in gro

pickupchik [31]

Answer:

finding Cepheid variable and measuring their periods.

Explanation:

This method is called finding Cepheid variable and measuring their periods.

Cepheid variable is actually a type of star that has a radial pulsation having a varying brightness and diameter. This change in brightness is very well defined having a period and amplitude.

A potent clear link between the luminosity and pulsation period of a Cepheid variable developed Cepheids as an important determinants of cosmic criteria for scaling galactic and extra galactic distances. Henrietta Swan Leavitt revealed this robust feature of conventional Cepheid in 1908 after observing thousands of variable stars in the Magellanic Clouds. This in fact turn, by making comparisons its established luminosity to its measured brightness, allows one to evaluate the distance to the star.

5 0

3 years ago

We have discovered some exoplanets that are still forming from a nebula. How might those planets change over time?

Rudik [331]

Based on several theories made by scientists, planets are formed because of the accumulation of gases and other particles that are attracted to each other. These accumulated gases form into clumps and eventually the clumps get bigger and turn into a big orbital mass. The exoplanets may experience change over time through the observance of its orbit in a particular axis, and if there are other debris that might affect the planet's continuous growth.

6 0

2 years ago