Physical Science Exam #2 (1D & 2D Kinematics)

The magnitude of the vertical velocity of a projectile is ALWAYS ____.

Changing (Gravity is exerting a force on the object. Therefore the vertical velocity is ALWAYS CHANGING (DECREASING))

The magnitude of the horizontal velocity of a projectile is ALWAYS ____

Constant (NEVER CHANGES)

The acceleration of a projectile is always directed

Downward

Two vectors with a magnitude of 5 units and 12 units are being added. The resultant vector could have a magnitude that ranges from ___ units to ___ units

First range: 12-5=7, Second range: 12+5=17

Which of the following statements are true of projectile motion?

Projectiles are objects that experience free fall, The acceleration of a projectile is downward, and Gravity is the only force influencing the motion of a project

In the Vector Addition Lab, the following data was collected for determining the displacement from the door of the Physics classroom to another location in the building: 2 m West22.0 mSouth25.0 m East9.0 mNorth4 mWest.The direction of the resultant displacement is closest to ___ degrees. (Use the counter-clockwise from East convention

Simply add the vectors. For the x-direction, we will call East positive. So, −2.0+25.0−4.0=19.0 m. For the x-direction, we will call North positive. So, 9.0−22.0=−13.0 m.The angle is theta=tan^−1(−13.019.0)=−34.4 degrees(aka 325.6 degrees)

A projectile is moving upwards and rightwards towards the peak of its trajectory. Which one of the following forces is acting upon the projectile during this portion of its flight?

The force of gravity, aka a downward force

A 50-N force is applied at 30 degrees (sometimes called 30 degrees north of east). This would be the same as applying two forces at __

43 N east and 25 N north, because The component of the force vector on the x-axis is Rx=(50)cos(30 degrees)=43 N and on the y-axis is Ry=(50)sin(30 degrees)=25 N.

A projectile is launched horizontally with a velocity of 50 m/s. After 4 seconds, the magnitude of the horizontal component of velocity is approximately ____ m/s and the magnitude of the vertical component of velocity is approximately ____

50, 40

If the pilot trying to get to a destination due west, and is flying in a wind that blows out of the north, then the pilot should head his plane in the direction of

A Vector going due west and downward

Which of the following objects are projectiles?

An object free falling only affected by the force of gravity, such as an apple free falling from a tall tree

A projectile islaunched from the ground at an angle to the horizontal and subsequently hits the ground at the same initial height. The projectile requires 3.0 seconds to reach the peak of its trajectory. Which of the following are true of the projectile?

The projectile will remain in the air for a total time of 6.0 seconds, and the initial vertical velocity of the projectile is about 30 m/s

Vectors A, B and C are being added using the head-to-tail method in order to determine the resultant. Vector A is added first, then B, then C. If the vectors were added in a different order, then the resultant would have

The same magnitude and direction (Order of Vector addition doesn't change result)

A 2-kg object is launched upwards and rightwards and subsequently experiences projectile motion. Just prior to reaching the peak of its trajectory, the net force on the 2-kg object is ____

approximately 20 N, directed downward

A 3-kg projectile is launched upward and rightward from ground level. The magnitude of the acceleration of the 3-kg projectile at the peak of its trajectory is ___ m/s/s

approximately 30

A projectile is launched horizontally. As it travels along its trajectory towardthe ground, the horizontal component of its velocity ____ and the vertical component of its velocity ___

remains the same, decreases

A truck drives down the road at a constant speed. A ball is launched from the back of the truck. By the time the ball returns to its original launch height, the truck is at the position shown. Assuming negligible air resistance on the ball, the ball would follow path

Y (same position as when launched) (The horizontal component of the ball's velocity is exactly the same as the horizontal truck velocity)

A projectile is launched horizontally and hits the ground in 0.50 second. If it is launched horizontally with twice the speed in the same direction, then it would hit the ground in

the same amount of time - 0.50 second

A projectile is launched upward at an angle to the horizontal. The initial horizontal velocity is 30 m/s; the initial vertical velocity is 50 m/s. After 4 seconds, the magnitude of the horizontal component of velocity is approximately ____ m/s and the magnitude of the vertical component of velocity is approximately ____ m

30, 10