Fill in the blanks to complete each statement about the heating of Earth's surface.

A ball is thrown straight up with enough speed so that it is in the air for several seconds. Assume the positive direction is up

Andrew [12]

Answer:

a) v= 0 m/s b) v= 6.86 m/s

Explanation:

a) When the ball reaches to its highest point, under the influence of gravity, before starting to fall down, it momentarily comes to an stop (this is needed prior to change direction in any movement), so, applying the definition of acceleration, and replacing the acceleration a by g, we have:

vf = v₀ - g*t (1)

The minus sign means that the acceleration due to gravity is always downward, so if we assume that the positive direction is upwards it must be negative.

At the highest point, vf= 0.

b) Prior to solve this point, we need to know which is the time when the ball reaches to its highest point.

As we know vf=0, we can solve (1) for t, as follows:

th = v₀/g

Now, for a time that is 0.7 s before this time, applying the acceleration definition and solving for v again, we have:

v = v₀ -(g *(th-0.7 s)), but th= v₀/g, so we get:

v= v₀ -g((v₀/g)-0.7 s) = v₀ - v₀ + g*0.7 s

⇒ v=g*0.7 s = 9.8 m/s²*0.7 s

⇒ v = 6.86 m/s

6 0

3 years ago

What is it called when something dissolves into something else

Evgen [1.6K]

Answer:

The correct answer is dissolving and the end product is a solution.

Explanation:

Solubility is an property of a substance to get dissolved into another. When a substance, termed as solute, dissolves in another substance, termed as solvent, we get a solution.

Larger molecules of the solute breaks because of weak covalent bonds between their molecules and pairs up with the smaller molecules of the solvent and thus dissolves in it. Not all elements can serve solutes or solvents as some have strong forces that bind them together. For example sugar is a solute in water but oil is not soluble in water.

7 0

3 years ago

The electric current leaves the battery passes through the it then travels through the next through the and finally padses throu

miss Akunina [59]

The answers are:

bulb, motor, buzzer and swtich.

As seen in the picture attached,

The electric current leaves the battery passes through the bulb. It then travels through the motor, next through the buzzer and finally passes through the switch before returning to the battery.

8 0

4 years ago

PLZ HELP PLZ ILL GIVE BRAINLIEST TO BEST ANSWERED

IRINA_888 [86]

Answer:

1.Contact because its a contact force

2 Contact because when the car is stopping it is coming in to contact with the ground.

3 non Contact because magnets don't need to have contact they pull

4 non Contact because its not a contact force

7 0

3 years ago

A bowler throws a bowling ball of radius R = 11.0 cm down the lane with initial speed = 8.50 m/s. The ball is thrown in such a w

Ad libitum [116K]

Answer:

a) 1.18 seconds

b) 8.6 m

c) 5.19 revolutions

d) 6.07 m/s

Explanation:

Step 1: Data given

radius of the ball = 11.0 cm

Initial speed of the ball = 8.50 m/s

The coefficient of kinetic friction between the ball and the lane is 0.210.

(a) For what length of time does the ball skid?

The velocity at time t can be written as v(t) = v0 + at

⇒ with v(t) = the velocity at time t

⇒ with v0 : the initial velocity = 8.50 m/s

⇒ with a = the acceleration (in m/s²)

⇒The acceleration (negative) due to friction: a = -µg

⇒ with µ = 0.210

⇒ with g = 9.81 m/s²

v(t) =8.5m/s - 0.21*9.81m/s² * t = 8.5 - 2.06t

Torque τ = Iα = (2m(0.11m)²/5)α = 0.00484m*α

τ = F * r = µm*g*R = 0.21 * M * 9.81m/s² * 0.11m = 0.227m

so α = 0.227m / 0.00484m = 46.9 rad/s²

angular velocity ω(t) = ωo + αt = 0 + 46.9 rad/s² * t

The ball stops sliding when v(t) = ω(t) * r

8.5 - 2.06t = 46.9*0.11*t = 5.159t

7.219t = 8.5

t = 1.18 seconds

b) How far down the lane does it skid?

s = Vo*t + ½at² = 8.5m/s * 1.18s - ½* 2.06 m/s² * (1.18s)² = 8.6 m

c) How many revolutions does it make before it starts to roll?

The angular acceleration of the ball is:

α = τ/I

⇒ with τ = the torque experienced by the ball due the frictional force

⇒ τ = fk*R

α = fk*R /I

⇒ I = 2/5 m*R²

⇒ fk = µk*m*g

α = (µk*m*g*R)/(2/5mR²)

α = 5µk*g /2R

The angular displacement of the ball is:

∅ = 1/2αt²

⇒ The ball does not have an initial angular velocity

∅ =1/2*(5µk*g/2)*t²

∅ = 5µkgt²/4R

∅ = (5*0.21*9.81*1.18²)/(4*11.0 *10^-2)

∅ = 32.6 rad

Number of revolutions = 32.6 rad /2π

Number of revolutions = 5.19

(d) How fast is it moving when it starts to roll?

v = Vo + at = 8.5m/s - 2.06m/s² * 1.18s = 6.07 m/s

7 0

3 years ago