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guapka [62]
3 years ago
9

Leah watches a toy car move across a table at a constant speed. The car moves across the table in one direction and falls off th

e other side. Leah decides to try another situation. She watches the car move across the table at a constant speed, then when it reaches the other side of the table, her friend Joey pushes the car in the other direction. The car moves back to Leah.
Based on Leah's informal experiment, what forces cause the car to change direction?
A.
balanced forces from Joey pushing the car
B.
unbalanced forces from Joey pushing the car
C.
unbalanced forces from Leah watching the car
D.
balanced forces from the car moving across the table
Physics
2 answers:
Sedbober [7]3 years ago
5 0

In order to change the direction and speed, a net external force is required. A net external force is an unbalanced force which will change the direction and gives the speed in the opposite direction. Hence, its an unbalanced force from the joey that pushes the car in the other direction due to which it the car starts to move back to Leah. Without, unbalanced force there is not change in the direction of the car's motion.

Hence, option B is correct.

zalisa [80]3 years ago
5 0

Answer:

B

Explanation:

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2. While standing near a bus stop, a student hears a distant horn beeping. The frequency emitted by the horn is 440 Hz. The bus
jarptica [38.1K]

Given Information:

Frequency of horn = f₀ = 440 Hz

Speed of sound = v = 330 m/s

Speed of bus = v₀ = 20 m/s

Answer:

Case 1. When the bus is crossing the student = 440 Hz

Case 2. When the bus is approaching the student = 414.9 Hz

Case 3. When the bus is moving away from the student = 468.4 Hz

Explanation:

There are 3 cases in this scenario:

Case 1. When the bus is crossing the student

Case 2. When the bus is approaching the student

Case 3. When the bus is moving away from the student

Let us explore each case:

Case 1. When the bus is crossing the student:

Student will hear the same frequency emitted by the horn that is 440 Hz.

f = 440 Hz

Case 2. When the bus is approaching the student

f = f₀ ( v / v+v₀ )

f = 440 ( 330/ 330+20 )

f = 440 ( 330/ 350 )

f = 440 ( 0.943 )

f = 414.9 Hz

Case 3. When the bus is moving away from the student

f = f₀ ( v / v+v₀ )

f = 440 ( 330/ 330-20 )

f = 440 ( 330/ 310 )

f = 440 ( 1.0645 )

f = 468.4 Hz

6 0
3 years ago
Suppose the odometer on our car is broken and we want to estimate the distance driven over a 30 second time interval. We take th
Natalija [7]

Let say for every 5 s of time interval the speed will remain constant

so it is given as

v(mi/h)   16    21    23    26    33    30     28

now we have to convert the speed into ft/s as it is given that 1 mi/h = 5280/3600 ft/s

so here we will have

v(ft/s)      23.5    30.8     33.73     38.13     48.4     44     41.1

now for each interval of 5 s we will have to find the distance cover for above interval of time

d = v \times t

d = (23.5 + 30.8 + 33.73 + 38.13 + 48.4 + 44 + 41.1) \times 5

d = 1298.1 ft

so here it will cover 1298.1 ft distance in 30 s interval of time

4 0
3 years ago
Read 2 more answers
Remember to include your data, equation, and work when solving this problem.
andrezito [222]

Answer:

F = 0.00156[N]

Explanation:

We can solve this problem by using Newton's proposed universal gravitation law.

F=G*\frac{m_{1} *m_{2} }{r^{2} } \\

Where:

F = gravitational force between the moon and Ellen; units [Newtos] or [N]

G = universal gravitational constant = 6.67 * 10^-11 [N^2*m^2/(kg^2)]

m1= Ellen's mass [kg]

m2= Moon's mass [kg]

r = distance from the moon to the earth [meters] or [m].

Data:

G = 6.67 * 10^-11 [N^2*m^2/(kg^2)]

m1 = 47 [kg]

m2 = 7.35 * 10^22 [kg]

r = 3.84 * 10^8 [m]

F=6.67*10^{-11} * \frac{47*7.35*10^{22} }{(3.84*10^8)^{2} }\\ F= 0.00156 [N]

This force is very small compare with the force exerted by the earth to Ellen's body. That is the reason that her body does not float away.

6 0
3 years ago
What is the definition of power.
Mandarinka [93]

Answer:

What is the definition of power.

Explanation:

ability to do or act; capability of doing or accomplishing something.

6 0
3 years ago
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Describe the main energy transformations that occur when an apple falls from a tree? ​
blondinia [14]

Answer:

Kinetic energy

Explanation:

When an apple falls from a tree it has to do with the energy from gravity. Gravity energy turns into kinetic energy once its in motion.

Sorry if im wrong

7 0
3 years ago
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