Physics 201 - Exam 1 Review
Vector A has magnitude 8.0 m at an angle of 30 degrees below the +x axis. The y component of A is
-4.0m
A plane flying horizontally at a speed of 50.0 m/s and at an elevation of 160 m drops a package. Two seconds later it drops a second package. How far apart will the two packages land on the ground
100m
If a ball is thrown with a velocity of 25 m/s at an angle of 37e above the horizontal, what is the vertical component of the velocity?
15 m/s
What is the percent uncertainty in the measurement 2.58 +/- 0.15 cm?
5.8%
A typical jetliner lands at a speed of 1.60 x 10^2 mi/h and decelerates at the rate of (10.0mi/h)/s . If the plane travels at a constant speed of 1.60 x 10^2 mi/h for 1.00 s after landing before applying the brakes, what is the total displacement of the aircraft between touchdown on the runway and coming to rest?
644 m
The traffic light turns green, and the driver of a high-performance car slams the accelerator to the floor. The accelerometer registers 22.0 m/s^2 . Convert this reading to km/min^2.
79.2 km/min^2
Compute the area for each of the following rooms: Banquet hall(L=14.71 m and W=7.46m), Meeting Room(L=4.822m and W=5.1m), and Dining Room(L=13.8m and W=9m). Then find the area of all three rooms combined.
Banquet Hall: 1.10 x 10^2 square meters Meeting Room: 25 square meters Dining Room: 100 square meters Total area: 2 x 10^2 square meters
A ball is thrown straight up, reaches a maximum height, then falls to its initial height. Make a statement about the direction of the velocity and acceleration as the ball is coming down
Both its velocity and its acceleration point downward
A shopper leaves home and drives to a store located 7.00 km away in a direction 30.0 degrees north of east. Leaving the store, the shopper drives 5.00 km in a direction 50.0 degrees west of north to a restaurant. Find the distance and direction from the shopper's home to the restaurant.
Distance: 7.07 km Direction: 71.6 degrees
When a football in a field goal attempt reaches its maximum height, how does its speed compare to its initial speed?
It is less than its initial speed
Suppose a ball is thrown downward in the absence of air resistance. Make a statement concerning its acceleration
Its acceleration is constant.
Suppose a ball is thrown straight up. Make a statement about the velocity and the acceleration when the ball reaches the highest point.
Its velocity is zero and its acceleration not zero.
Suppose a ball is thrown straight up, reaches a maximum height, then falls to its initial height. Make a statement about the direction of the velocity and acceleration as the ball is going up
Its velocity points upward and its acceleration points downward.
When is average velocity is equal to instantaneous velocity?
Only when velocity is constant
When looking in the direction of a ball in free fall, at the maximum height V=0. What is the acceleration?
The acceleration is gravity
Under what condition is the average velocity equal to the average of the object's initial and final velocity?
The acceleration must be constant.
Make a comparison between displacement and distance traveled.
The displacement is either less than or equal to the distance travel.
If a car is traveling at a speed of 28.0 m/s, is the driver exceeding the speed limit 55.0 of mi/h? (Note: There is 1609 meters per mile) (Conversion factors problem)
The driver is exceeding the speed limit because he is driving 62.6 mi/h
When moving in the x direction, the velocity is constant. What is the acceleration?
There is no acceleration
Can an object's velocity change when its acceleration is constant? Support your answer with an example.
Yes; an example is a rock thrown up in the air.
A jet plane traveling horizontally at 1.00 x 10^2 m/s drops a rocket from a considerable height. (See Fig. 3.13.) The rocket immediately fires its engines, accelerating at 20.0 m/s^2 in the x-direction while falling under the influence of gravity in the y-direction. When the rocket has fallen 1.00 km, find (a)its velocity in the y-direction, (b)its velocity in the x-direction, and (c)the magnitude and direction of its velocity. Neglect air drag and aerodynamic lift.
a.) -1.40 x 10^2 m/s b.) 386 m/s c.) Magnitude: 411 m/s and Direction: -19.9 degrees
A train is traveling with a speed of 15 m/s relative to Earth. A passenger standing at the rear of the train pitches a baseball with a speed of 15 m/s relative to the train off the back end, in the direction opposite the motion of the train. (a)What is the velocity of the baseball relative to Earth? (b)What is the velocity of the baseball relative to the Earth if thrown in the opposite direction at the same speed?
a.) 0 b.) 3.0 x 10^1 m/s
A long jumper (Fig. 3.11) leaves the ground at an angle of 20.0 degrees to the horizontal and at a speed of 11.0 m/s. (a)How long does it take for him to reach maximum height? (b)What is the maximum height? (c)How far does he jump? (Assume his motion is equivalent to that of a particle, disregarding the motion of his arms and legs.) (d)Use Equation 3.9c to find the maximum height he reaches.
a.) 0.384 s b.) 0.722 m c.) 7.94 m d.) 0.722 m
A car traveling at a constant speed of 24.0 m/s passes a trooper hidden behind a billboard, as in Figure 2.17. One second after the speeding car passes the billboard, the trooper sets off in chase with a constant acceleration of 3.00 m/s^2. (a)How long does it take the trooper to overtake the speeding car? (b)How fast is the trooper going at that time?
a.) 16.9s b.) 50.7 m/s
A race car starting from rest accelerates at a constant rate of 5.00m/s^2. (a)What is the velocity of the car after it has traveled 1.00x10^2 ft? (b)How much time has elapsed? (c)Calculate the average velocity two different ways.
a.) 17.5 m/s b.) 3.50s c.)8.71 m/s and 8.75 m/s
An Alaskan rescue plane drops a package of emergency rations to stranded hikers, as shown in Figure 3.10. The plane is traveling horizontally at 40.0 m/s at a height of 1.00x10^2 m above the ground. Neglect air resistance. (a)Where does the package strike the ground relative to the point at which it was released? (b)What are the horizontal and vertical components of the velocity of the package just before it hits the ground? (c)What is the angle of the impact?
a.) 181 m b.) Vx=40.0 m/s and Vy= -44.3 m/s c.) -48.0 degrees
A ball is thrown from the top of a building with an initial velocity of 20.0 m/s straight upward, at an initial height of 50.0 m above the ground. The ball just misses the edge of the roof on its way down, as shown in Figure 2.20. Determine (a)the time needed for the ball to reach its maximum height, (b)the maximum height, (c)the time needed for the ball to return to the height from which it was thrown and the velocity of the ball at that instant, (d)the time needed for the ball to reach the ground, and (e)the velocity and position of the ball at t=5.00 s. Neglect air drag.
a.) 2.04 s b.) 20.4 m c.) 4.08 s and -20.0 m/s d.) 5.83 s e.) -29.0 m/s and -22.5 m
A turtle and a rabbit engage in a footrace over a distance of 4.00 km. The rabbit runs 0.500 km and then stops for a 90.0-min nap. Upon awakening, he remembers the race and runs twice as fast. Finishing the course in a total time of 1.75 h, the rabbit wins the race. (a)Calculate the average speed of the rabbit. (b)What was his average speed before he stopped for a nap? Assume no detours or doubling back.
a.) 2.29 km/h b.) 9.0km/h
A person measures the height of a building by walking out a distance of 46 m from its base and shining a flashlight beam towards the top. When the beam is elevated at an angle of 39 degrees with respect to the horizontal, as shown in Figure 1.9, the beam just strikes the top of the building. a.) If the flashlight is held at a height of 2 m, find the height of the building. b.) Calculate the length of the light beam.
a.) 39.3 m b.) 59.2 m
A ball is thrown upward from the top of a building at an angle of 30.0 degrees above the horizontal and with an initial speed of 20.0 m/s, as in Figure 3.12. The point of release is 45.0 m above the ground. (a)How long does it take for the ball to hit the ground? (b)Find the ball's speed at impact. (c)Find the horizontal range of the ball. Neglect air resistance.
a.) 4.22 s b.) 35.9 m/s c.) 73.1 m
A hiker begins a trip by first walking 25.0 km 45 degrees south of east from her base camp. On the second day she walks 40.0 km in a direction 60 degrees north of east, at which point she discovers a forest ranger's tower. (a)Determine the components of the hiker's displacements in the first and second days. (b)Determine the components of the hiker's total displacement for the trip. (c)Find the magnitude and direction of the displacement from base camp.
a.) Ax=17.7km, Ay=-17.7km, Bx=20.0km, By=34.6km b.) Rx=37.7km and Ry=16.9km c.) Magnitude of R=41.3km and Direction: 24.1 degrees
A rocket moves straight upward, starting from rest with an acceleration of +29.4 m/s^2. It runs out of fuel at the end of 4.00 s and continues to coast upward, reaching a maximum height before falling back to Earth. (a)Find the rocket's velocity and position at the end of 4.00 s. (b)Find the maximum height the rocket reaches. (c)Find the velocity the instant before the rocket crashes on the ground.
a.) Vb=118 m/s and Yb=235 m b.) 945 m c.) -136 m/s
A car going from "0 to 60 in 8s". This is a description of
average acceleration
An athlete participates in a long-jump competition, leaping into the air with a velocity V(initial) at an angle Theta(initial) with the horizontal. Obtain an expression for the length of the jump in terms of V(initial), Theta(initial), and g.
delta X= ( V(initial)^2 sin 2Theta(initial) ) / g
A package of supplies is dropped from a plane, and one second later a second package is dropped. Neglecting air resistance, the distance between the falling packages will
increase
Object moving in +x axis at an acceleration of 2.0 m/s^2 means that the object is
increasing its velocity by 2.0 m/s in every second.
If the velocity is zero, does it mean the acceleration is zero? Support your answer with an example.
no; an example would be an object starting from rest.
A vector cannot have a zero magnitude if
one of its components is not zero
A vector quantity could be
velocity
