All categories

3 years ago

Karen is running forward at a speed of 9 m/s. She tosses her sweaty headband backward at a speed of 20 m/s.

Physics

2 answers:

Anika [276]3 years ago

7 0

Answer:

The speed of the headband, to the nearest whole number relative to a stationary observer watching Karen, is 11m/s

Explanation:

The velocity of the headband relative to the stationary observer is equal to the velocity of Karen relative to the stationary observer plus the velocity of the headband relative to Karen. Mathematically:

$V_{H} =V_{K}+V_{H/K}$

Where:

$V_{K}=9m/s$

$V_{HK}=-20m/s$ (it's negative because it mover backward)

$V_{H}$ : velocity of the headband relative to the stationary observer

Plugging these values

$V_{H} =9m/s-20m/s=-11m/s$

Speed is simply the magnitude of velocity or its absolute value, that is to say, 11m/s (positive)

jolli1 [7]3 years ago

6 0

11 miles away from the direction she was running

You might be interested in

Express the vector R B in terms of A, B, C, and Ď, the edges of a parallelogram.

Vadim26 [7]

Answer:

R=0.5B+0.5C+2A+D

Explanation:

By the triangular law of vector addition

vector R= vector B- vector D

As A,B,C,D are edges of the parallelogram,

A is parallel to D but opposite in direction.

Therefore

$A = (-D)$ ; $A//D$ ;

$2A=-2D$

B is parallel to C and in same direction.

$B//C\\B=C\\$

$0.5B=0.5C\\$

$R= B-D;\\R= 0.5B+0.5B-D;\\R=0.5B+0.5C-D;\\R=0.5B+0.5C-2D+D;\\R=0.5B+0.5C+2A+D;$

7 0

2 years ago

What average power must be supplied to the rope to generate sinusoidal waves that have amplitude 0.200 m and wavelength 0.600 m

pychu [463]

Complete question:

A taut rope has a mass of 0.123 kg and a length of 3.54 m. What average power must be supplied to the rope to generate sinusoidal waves that have amplitude 0.200 m and wavelength 0.600 m if the waves are to travel at 28.0 m/s ?

Answer:

The average power supplied to the rope to generate sinusoidal waves is 1676.159 watts.

Explanation:

Velocity = Frequency X wavelength

V = Fλ ⇒ F = V/λ

F = 28/0.6 = 46.67 Hz

Angular frequency (ω) = 2πF = 2π (46.67) = 93.34π rad/s

Average power supplied to the rope will be calculated as follows

$P_{avg} =\frac{1}{2} \mu \omega^2 A^2 V$

where;

ω is the angular frequency

A is the amplitude

V is the velocity

μ is mass per unit length = 0.123/3.54 = 0.0348 kg/m

$P_{avg} =\frac{1}{2} ( 0.0348)(93.34 \pi )^2 (0.2)^2 (28)$ = 1676.159 watts

The average power supplied to the rope to generate sinusoidal waves is 1676.159 watts.

6 0

2 years ago

One of your classmates, in a fit of unrestrained ego, jumps onto a lab table:

Anettt [7]

The equilibrium condition allows finding the results for the forces of the system are

a) The free body diagram is in the attachment

b) The normal force is N = 737 N

c) The mass of the table is 10.2 kg

Newton's second law indicates that the net force is proportional to the product of the mass and the acceleration of the bodies, in the special case that the acceleration is zero, it is called the equilibrium condition

∑ F = 0

Where the bold letters indicate vectors, F is the external forces

a) A free body diagram is a scheme of the forces without the details of the bodies, in the attachmentt we see a free body diagram of the system.

b) The reaction force of the ground is applied in each of the legs of the table, in general this force has the same magnitude in each leg, therefore in Newton's second law we can place it as a single force

N = N₁ + N₂ + N₃ + N₄₄

Let's apply the equilibrium condition

N - $W_m -w_{table}$ = 0