What force keeps the outside of a bicycle wheel from flying off?

A car starts from rest and after 20 seconds it's velocity becomes 108km find the acceleration of the car

andre [41]

Answer:

1.5 km/s²

Explanation:

Given that:

a car starts from rest; it means the initial velocity (u) = 0 km/hr = 0 m/s

after time (t) = 20 seconds

the final velocity = 108 km/hr = 30 m/s

The acceleration (a) of the car can be determined by using the formula:

$a = \dfrac{v-u}{t}$

$a = \dfrac{30\ m/s -0 \ m/s}{20 \ s}$

$a = \dfrac{30 \ m/s}{20 \ s}$

a = 1.5 km/s²

7 0

3 years ago

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

A free-body diagram is a special example of the vector diagrams that will

Genrish500 [490]

From someone who has taken physics this is, True

6 0

3 years ago

You stand on a bridge above a river and drop a rock into the water below from a height of 25 m. (Assume no air resistance)

Ilia_Sergeevich [38]

PART a)

here when stone is dropped there is only gravitational force on it

so its acceleration is only due to gravity

so we will have

$a = g = 9.8 m/s^2$

Part b)

Now from kinematics equation we will have

$y = v_i t + \frac{1}{2} at^2$

now we have

y = 25 m

so from above equation

$25 = 0 + \frac{1}{2}(9.8 )t^2$

$t = 2.26 s$

Part c)

If we throw the rock horizontally by speed 20 m/s

then in this case there is no change in the vertical velocity

so it will take same time to reach the water surface as it took initially

So t = 2.26 s

Part D)

Initial speed = 20 m/s

angle of projection = 65 degree

now we have

$v_x = vcos\theta$

$v_x = 20 cos65 = 8.45 m/s$

$v_y = vsin\theta$

$v_y = 20 sin65 = 18.13 m/s$

PART E)

when stone will reach to maximum height then we know that its final speed in y direction becomes zero

so here we can use kinematics in Y direction

$v_f - v_y = at$

$0 - 18.13 = (-9.8) t$

$t = 1.85 s$

so it will take 1.85 s to reach the top

5 0

3 years ago

A conducting sphere contains positive charge distributed uniformly over its surface. Which statements about the potential due to

stira [4]

Answer:

a. FALSE

b. FALSE

c. TRUTH

d. FALSE

e. FALSE

Explanation:

To determine which statements are truth or false you focus in the following formula, for the electric potential generated by a conducting sphere:

$V=\frac{Q}{4\pi \epsilon_o R}$ inside the sphere

$V'=\frac{Q}{4\pi \epsilon_o r}$ for r > R (outside the sphere)

R: radius of the sphere

ε0: dielectric permittivity of vacuum

Q: charge of the sphere

As you can notice, inside the sphere the potential is constant. Inside the sphere, the potential is the same. Outside the surface the potential decreases as 1/r, being r the distance to the center of the sphere.

Hence, you can conclude:

a. The potential at the center of the sphere is zero. FALSE

b.The potential is lowest, but not zero, at the center of the sphere. FALSE

c. The potential at the center of the sphere is the same as the potential at the surface. TRUTH

d. The potential at the center is the same as the potential at infinity. FALSE

e. The potential at the surface is higher than the potential at the center. FALSE

8 0

3 years ago