When a projectile is fired at 45 deg. angle and is in free fall, the only point along the path that the acceleration of the object is zero is the instant when the object is at the highest point of its path.
Answer: False
Can someone explain how?
2.) An object with acceleration in the positive x-direction (to the right) must be moving to the right.
False: Why?
4.) An object starting from ground level that is projected with the initial velocity at a 45 deg. angle upward will have the exact same velocity right before it hits the ground some time later.
FALSE
Explanation please?
6.) If an objects velocity over a given time period is zero, then the object was at rest for that time period.
FALSE
Explanation please?
When a projectile is fired at 45 deg. angle and is in free fall, the only point along the path that the acceleration of the object is zero is the instant when the object is at the highest point of its path.
Answer: False
Can someone explain how?
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F = m a
the force is constant = m g
so the whole time the acceleration is 9.81 m/s^2 down
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2.) An object with acceleration in the positive x-direction (to the right) must be moving to the right.
False: Why?
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If you are going left, negative x speed at 10 m/s
and put the brakes on.
Your acceleration is + to the right
F = m a again :)
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4.) An object starting from ground level that is projected with the initial velocity at a 45 deg. angle upward will have the exact same velocity right before it hits the ground some time later.
FALSE
Explanation please?
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Due to symmetry it will have the same SPEED
BUT
NOT the same velocity vector because the vertical component of velocity is now DOWN
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6.) If an objects velocity over a given time period is zero, then the object was at rest for that time period.
FALSE
Explanation please?
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True as far as I know. If it is not moving it is at rest.
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1) When a projectile is fired at a 45-degree angle and is in free fall, the only point along the path where the acceleration of the object is zero is the instant when the object is at the highest point of its path.
Explanation: This statement is false. When a projectile is in free fall, it experiences a constant acceleration due to gravity, which is directed downward. Although the magnitude of the acceleration remains constant, its direction changes continuously. At the highest point of the path, the object momentarily stops moving vertically, but it still accelerates horizontally due to gravity. Therefore, the acceleration of the object is never zero along the path.
2) An object with acceleration in the positive x-direction (to the right) must be moving to the right.
Explanation: This statement is false. Acceleration is a measure of how quickly an object's velocity changes. If an object has a positive acceleration in the x-direction, it means that its velocity is increasing in the positive x-direction. However, this does not imply that the object is necessarily moving to the right. The object could be moving to the left initially, and the positive acceleration could be slowing its speed in that direction, eventually causing it to reverse its motion and move to the right.
4) An object starting from ground level that is projected with the initial velocity at a 45-degree angle upward will have the exact same velocity right before it hits the ground some time later.
Explanation: This statement is false. When an object is projected upward at a 45-degree angle, it follows a parabolic trajectory due to the influence of gravity. As the object rises, its velocity decreases until it reaches its maximum height. At this point, the object momentarily comes to a halt before it starts descending. During the downward motion, its velocity steadily increases until it hits the ground. Hence, the object's velocity right before it hits the ground will be greater than its initial velocity.
6) If an object's velocity over a given time period is zero, then the object was at rest for that time period.
Explanation: This statement is false. Velocity measures the rate of change of an object's displacement and includes both magnitude and direction. If an object's velocity is zero over a given time period, it means that the object is not changing its position during that time. However, it does not necessarily imply that the object was at rest. The object could have been moving at some other point in time during that period and then returned to its initial position, resulting in a net displacement of zero.