1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Oksanka [162]
3 years ago
6

When Marie sees the red traffic light, Marie brakes to a halt from a speed of 70 m/s in just 2 seconds. What is her deceleration

?
Physics
1 answer:
SashulF [63]3 years ago
7 0

Answer:

-35 m/s^2

Explanation:

<u>Deceleration is the complete opposite of acceleration and is calculated by adding a negative sign to the formula for finding acceleration.</u>

Since acceleration is calculated by diving the change in velocity with time, deceleration will become:

 Deceleration =   -Δv/t, where Δv = change in velocity and t = time

In this case, Δv = 70 m/s and t = 2 s, hence;

Deceleration = -70/2 = -35 m/s^2

<em>The deceleration is 35 </em>m/s^2<em>.</em>

You might be interested in
An American traveler in China carries a transformer to convert China's standard 220 V to 120 V so that she can use some small ap
Arisa [49]

Answer:

(a) The ratio of turns in the primary and secondary coils of her transformer is 1.833

(b) The ratio of input to output current is 0.55

(c) To increase the output voltage, you can either increase the number of turns in the secondary coil (step-up) or increase the input current. Therefore, the Chinese person has to increase the input current of the transformer to achieve an increased output voltage that can power her 220 V appliances.

Explanation:

Given;

input voltage, V_p = 220 V

output voltage, V_s = 120 V

General transformer equation is given as;

\frac{V_p}{V_s} = \frac{N_p}{N_s} = \frac{I_s}{I_p}

where;

Np is number of turns in the primary coil

Ns is number of turns in the secondary coil

Is - is the secondary current or output current

Ip - is the primary current or input current

(a) The ratio of turns in the primary and secondary coils of her transformer;

\frac{N_p}{N_s} = \frac{V_p}{V_s} \\\\\frac{N_p}{N_s} = \frac{220}{120} = 1.833

(b) The ratio of input to output current;

\frac{I_p}{I_s} = \frac{V_s}{V_p} \\\\\frac{I_p}{I_s} = \frac{120}{220} \\\\\frac{I_p}{I_s} = 0.55

(c) To increase the output voltage, you can either increase the number of turns in the secondary coil (step-up) or increase the input current. Therefore, the Chinese person has to increase the input current of the transformer to achieve an increased output voltage that can power her 220 V appliances.

8 0
3 years ago
A small sphere is at rest at the top of a frictionless semicylindrical surface. The sphere is given a slight nudge to the right
V125BC [204]

Answer:

vi = 4.77 ft/s

Explanation:

Given:

- The radius of the surface R = 1.45 ft

- The Angle at which the the sphere leaves

- Initial velocity vi

- Final velocity vf

Find:

Determine the sphere's initial speed.

Solution:

- Newton's second law of motion in centripetal direction is given as:

                         m*g*cos(θ) - N = m*v^2 / R

Where, m: mass of sphere

             g: Gravitational Acceleration

             θ: Angle with the vertical

             N: Normal contact force.

- The sphere leaves surface at θ = 34°. The Normal contact is N = 0. Then we have:

                         m*g*cos(θ) - 0 = m*vf^2 / R

                         g*cos(θ) = vf^2 / R    

                         vf^2 = R*g*cos(θ)

                         vf^2 = 1.45*32.2*cos(34)

                        vf^2 = 38.708 ft/s

- Using conservation of energy for initial release point and point where sphere leaves cylinder:

                          ΔK.E = ΔP.E

                          0.5*m* ( vf^2 - vi^2 ) = m*g*(R - R*cos(θ))

                          ( vf^2 - vi^2 ) = 2*g*R*( 1 - cos(θ))

                          vi^2 =  vf^2 - 2*g*R*( 1 - cos(θ))

                          vi^2 = 38.708 - 2*32.2*1.45*(1-cos(34))

                          vi^2 = 22.744

                           vi = 4.77 ft/s

4 0
3 years ago
Why might scientists measure the mass of object rather than the weight of an object?
Marina CMI [18]
Because they have different measurements and weight and mass and some measurements are the same

3 0
3 years ago
Which of the following describes a risk associated with the use of hydropower as an energy source?
castortr0y [4]
Its A: the use of hydropower often changes the natural flow of water through an ecosystem 

add me on robloxs <span />
5 0
3 years ago
How much heat is needed to melt 13.74 kg of silver that is initially at 20°C?
salantis [7]

Answer:

Q = 4.63 \times 10^6 J

Explanation:

As we know that melting point of silver is

T = 961.8 degree C

Latent heat of fusion of silver is given as

L = 111 kJ/kg

specific heat capacity of silver is given as

s = 240 J/kg C

now we will have

Q = ms\Delta T + mL

\Delta T = 961.8 - 20

\Delta T = 941.8 degree C

now from above equation

Q = (13.74)(240)(941.8) + (13.74)(111 \times 10^3)

Q = 3.1 \times 10^6 + 1.53 \times 10^6

Q = 4.63 \times 10^6 J

3 0
3 years ago
Other questions:
  • What are the two most important properties of a telescope?
    5·1 answer
  • Lance armstrong biking over 40 miles in one day would be considered muscular strength. true or false
    9·1 answer
  • The Hubble Space Telescope is stabilized to within an angle of about 2-millionths of a degree by means of a series of gyroscopes
    7·1 answer
  • When comparing the three atomic models provided, which statement best describes the diagram?
    8·1 answer
  • A proton is released from rest in a uniform electric field. After the proton has traveled a distance of 10.0 cm, its speed is 1.
    13·1 answer
  • Do you think the electron will feel a force towards the proton, or away from it due to the proton's electric field? Given that,
    8·1 answer
  • imagine you are working as a rollercoaster designer. you are building a ride the top speed of a 65m/s at the bottom of the first
    14·1 answer
  • n astronaut has left the International Space Station to test a new space scooter. Her partner measures the following velocity ch
    6·1 answer
  • A vector has components x=6 m and y=8 m. what is its magnitude and direction?
    9·1 answer
  • Help pleasseeee URGENT
    7·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!