Newton's first law and projectiles questions

In summary, Mia Edwards is running the 200 meter dash with an acceleration of 0.9 m/s2. Inertia is the tendency of an object to resist change. If her acceleration is non-zero and in the same direction as her velocity, her velocity will increase. After 5 seconds, Mia reaches a velocity of 4.5 m/s2. It is unclear if she breaks the world record for the 200 meter race. Luke, an archer in the war, fires an arrow at 100 fps at 55 degrees above the horizontal ground. To calculate sine on a triangle, you divide the opposite by the hypotenuse, while cosine is calculated with the adjacent divided by the hypotenuse. If gravity works
  • #1
emma934
3
0
I just don't get these questions...please help.
() are what I think the answers are but I am not positive.
Question set 1:
Beginning from rest, Mia Edwards runs the 200 meter dash with an acceleration of 0.9 m/s2.
1. define inertia. (inertia- the tendency of an object to resist change)
2. what happens to Mia's velocity if acceleration is non-zero and in the same direction as her velocity? (if her acceleration is non-zero and in the same direction as her velocity than her velocity will increase.)
3. what is the highest velocity Mia reaches after 5 seconds? (4.5 m/s2)
4. the world record for the 200 meter race is 21.34 seconds. does she break the world record?
5. what would be the break down? acceleration second by second?
Question set 2:
Luke is an archer in the war. Using a bowl, he fires an arrow at 100 feet per second (fps) at 55 degrees above the horizontal ground.
1. what parts of a triangle are used for sine? what parts of a triangle are used for cosine? (to calculate sine on a triangle you divided the opposite by the hypotenuse. Cosine is calculated with the adjacent divided by the hypotenuse.
2. what should happen to arrow's vertical velocity as it comes down if gravity works in the same direction? (it gravity works in the same direction as the arrows then the vertical velocity of the arrow will increase.)
3. How long is the arrow in the air for in total?
4. Luke’s target is 613 feet away. Will he hit it?
 
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  • #2
emma934 said:
I just don't get these questions...please help.
() are what I think the answers are but I am not positive.
Question set 1:
Beginning from rest, Mia Edwards runs the 200 meter dash with an acceleration of 0.9 m/s2.
1. define inertia. (inertia- the tendency of an object to resist change)
2. what happens to Mia's velocity if acceleration is non-zero and in the same direction as her velocity? (if her acceleration is non-zero and in the same direction as her velocity than her velocity will increase.)
3. what is the highest velocity Mia reaches after 5 seconds? (4.5 m/s2)
4. the world record for the 200 meter race is 21.34 seconds. does she break the world record?
i.e. how long would it take mia to run 200m given the information so far?

5. what would be the break down? acceleration second by second?
... well, what happens to the acceleration?

Question set 2:
Luke is an archer in the war. Using a bowl, he fires an arrow at 100 feet per second (fps) at 55 degrees above the horizontal ground.
Presumably Luke uses a bow, not a bowl?

1. what parts of a triangle are used for sine? what parts of a triangle are used for cosine? (to calculate sine on a triangle you divided the opposite by the hypotenuse. Cosine is calculated with the adjacent divided by the hypotenuse.
2. what should happen to arrow's vertical velocity as it comes down if gravity works in the same direction? (it gravity works in the same direction as the arrows then the vertical velocity of the arrow will increase.)
3. How long is the arrow in the air for in total?
Time to go from the ground, to it's highest point, back to the ground again?
The speed when it hits the ground is the same as the initial speed.
You need to divide the motion into horizontal and vertical components to work this out.

4. Luke’s target is 613 feet away. Will he hit it?
... you need to do (3) first. What is the horizontal acceleration?
 

1. What is Newton's first law?

Newton's first law, also known as the law of inertia, states that an object will remain at rest or in motion with a constant velocity unless acted upon by an external force.

2. How does Newton's first law apply to projectiles?

Newton's first law applies to projectiles by explaining how they continue to move in a straight line with a constant velocity, known as inertia, unless acted upon by an external force such as gravity or air resistance.

3. What is the difference between a projectile and a free-falling object?

A projectile is an object that is launched into the air and moves under the influence of gravity, while a free-falling object is an object that is only under the influence of gravity and falls without any initial velocity.

4. How does air resistance affect projectiles?

Air resistance, also known as drag, can affect the motion of projectiles by slowing them down as they move through the air. This is due to the force of air pushing against the projectile in the opposite direction of its motion.

5. How does the angle of launch affect the range of a projectile?

The angle of launch, also known as the angle of elevation, can affect the range of a projectile by determining the initial velocity and direction of the projectile. The optimal angle for maximum range is 45 degrees, as it allows for the most efficient use of the projectile's initial velocity.

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