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UNO [17]
4 years ago
13

A runner starts slowing down as she gets tired. At 10 seconds, she 8m/a, and slows down to 2m/a at 13 seconds. What is her accel

eration.
Physics
1 answer:
ira [324]4 years ago
3 0

Magnitude of acceleration = (change in speed) / (time for the change) .

Change in speed = (end speed) - (start speed)
                            =        (2 m/a)  -  (8 m/a)  =  -6 m/a .

Time for the change = (end time) - (start time)
                                 =   (13 sec)  -  (10 sec)  =  3 sec .

Magnitude of acceleration =  (-6 m/a) / (3 sec)

                                          =       -2 m/a per second .
 
(That's the best I can do with the ambiguous units.
What unit of speed is 'm/a' ?  Is that "miles per afternoon" ?)

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The temperature at a point (x, y) on a flat metal plate is given by T(x, y) = 54/(7 + x2 + y2), where T is measured in °C and x,
ANTONII [103]

Answer:

dt/dx = -0.373702

dt/dy =  -1.121107

Explanation:

Given data

T(x, y) = 54/(7 + x² + y²)

to find out

rate of change of temperature with respect to distance

solution

we know function

T(x, y) = 54 /( 7 + x² + y²)

so derivative it x and y direction i.e

dt/dx = -54× 2x / (7 +x² + y²)²    .........................1

dt/dy = -54× 2y / (7 + x² + y²)²      .........................2

now put the value point (1,3) as x = 1 and y = 3 in equation 1 and 2

dt/dx = -54× 2(1) / (7 +(1)² + (3)²)²  

dt/dx = -0.373702

and

dt/dy =  -54× 2(3) / (7 + (1)² + (3)²)²

dt/dy =  -1.121107

7 0
3 years ago
What is number 30,31 in this picture?
Maslowich
On question 30, that is a displacement- time graph (DT). On this type of graph the gradient is equal to the velocity. B has the steepest gradient, then A and finally C

Now velocity is a vector quantity so it has a direction and speed ( speed doesn't have a fixed direction.)

on the DT graph im going to assume that movement B is a positive velocity with A and C being negative. 
So by ranking these: A is the most negative, C is the least negative and B has to be the greatest as it is the only positive velocity. 

Q31, The same type of graph is present, by looking at the gradients we can rank the largest and smallest velocities- speeds in the case of the question. 
i'll skip my working out as its the same as before:

C, B, A and then D

the same idea as on Q30 applies to Q31 part b, 

D,C,B then A 
6 0
3 years ago
PLEASE HELP URGENT: Please see attachment for problem! AP physics projectile question. I'd REALLY appreciate any help.
kiruha [24]
I’m so sorry, I need more information. Good luck and I’m sorry I couldn’t help you :(
4 0
4 years ago
A mass weighing 4 pounds is attached to a spring whose constant is 2 lb/ft. The medium offers a damping force that numerically e
Neko [114]

Answer:

the time at which it passes through the equilibrum position is:

t = 0.1 second

Explanation:

given

w= 4pounds

k(spring constant) = 2lb/ft

g(gravitational constant) = 10m/s² = 32ft/s²

β(initial point above equilibrum) = 1

velocity = 14ft/s

attached is an image showing the calculations, because some of the parameters aren't convenient to type.

3 0
3 years ago
A 2200 kg SUV traveling at 23.9 m/s can be stopped in 0.16 s if it hits a concrete wall. Assume that a 60 kg person was in the c
Jlenok [28]

Answer:

8962.5 N

Explanation:

From fundamental kinematics equations, acceleration, a is given by a=\frac {v-u}{t} where v is final velocity, u is initial velocity and t is time

We also know that force is a product of mass and acceleration of an object and substituting a=\frac {v-u}{t}  in the formula F=ma we obtain

F=ma=m\frac {v-u}{t}  where m is the mass of the body

F=60\times\frac {0-23.9}{0.16}=-8962.5 N

Therefore, the force is 8962.5 N

4 0
4 years ago
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