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3 years ago

Select the correct answer.

Physics

1 answer:

Marianna [84]3 years ago

6 0

Answer:

Explanation:

According to Newton's second law, acceleration is directly proportional to the net force. As the acceleration increases (when mass is constant), the net force increases. This is represented in the following formula.

$f = ma$

$a = \frac{f}{m}$

a = acceleration

f = force

m = mass

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30 km/h is _________m/s? A.)8.3 B.)5.6 C.)13.9 D.)11.1

Juli2301 [7.4K]

Answer:

Correct Option :- A

Explanation:

3 0

1 year ago

A) 1.2-kg ball is hanging from the end of a rope. The rope hangs at an angle 20° from the vertical when a 19 m/s horizontal wind

Marat540 [252]

Answer:

Part a)

$F_v = 4.28 N$

Part B)

$L = 1.02 m$

Part C)

$v = 1.25 m/s$

Explanation:

Part A)

As we know that ball is hanging from the top and its angle with the vertical is 20 degree

so we will have

$Tcos\theta = mg$

$T sin\theta = F_v$

$\frac{F_v}{mg} = tan\theta$

$F_v = mg tan\theta$

$F_v = 1.2\times 9.81 (tan20)$

$F_v = 4.28 N$

Part B)

Here we can use energy theorem to find the distance that it will move

$-\mu mg cos\theta L + mg sin\theta L = -\frac{1}{2}mv^2$

$(-(0.37)m(9.81) cos15 + m(9.81) sin15)L = - \frac{1}{2}m(1.4)^2$

$(-3.5 + 2.54)L = - 0.98$

$L = 1.02 m$

Part C)

At terminal speed condition we know that

$F_v = mg$

$bv^2 = mg$

$2.5 v^2 = 3.9$

$v = 1.25 m/s$

7 0

2 years ago

In a cup game if the teams have the same score at the end of the match, 30 minutes of ------- are played.

Alina [70]

Answer:

second lag

Explanation:

If in a cup game, a specified time limit is assigned to both teams to score high. If both teams are unable to score or if score of both the teams is equal then there is another second lag played where each team tries to score high. Even if in second lag both teams fail to score higher than other the last third lag is played or else game is declared draw.

5 0

2 years ago

Contrast elastic potential energy and chemical potential energy

tatuchka [14]

Chemical Potential Energy is released when chemical bonds between atoms are broken (like covalent and ionic) and is released mainly as thermal
Elastic Potential is released when the molecules in the material are allowed to go back to there original form, and is released mainly as kinetic

3 0

2 years ago

You are in charge of designing a movie stunt for a new Fast and Furious film. In this scene a stunt person has to jump from a br

blondinia [14]

Answer:

103.5 meters

Explanation:

Given that a stunt person has to jump from a bridge and land on a boat in the water 22.5 m below. The boat is cruising at a constant velocity of 48.3 m/s towards the bridge. The stunt person will jump up at 6.45 m/s as they leave the bridge.

The time the person will jump to a certain spot under the bridge can be calculated by using the formula below:

h = Ut + 1/2gt^2

since the person will fall under gravity, g = 9.8 m/s^2

Also, let assume that the person jump from rest, then, U = 0

Substitute h, U and g into the formula above

22.5 = 1/2 * 9.8 * t^2

22.5 = 4.9t^2

t^2 = 22.5/4.9

t^2 = 4.59

t = $\sqrt{4.592}$

t = 2.143 seconds

From definition of speed,

speed = distance /time

Given that the boat is cruising at a constant velocity of 48.3 m/s towards the bridge, substitute the speed and the time to get the distance.

48.3 = distance / 2.143

distance = 48.3 * 2.143

distance = 103.5 m

Therefore, the boat should be 103.5m away from the bridge at the moment the stunt person jumps?

3 0

2 years ago