Flashcards
Physics: Semester 1 Exam
Flashcards do conjunto (39)
- 1A vector is different from a scalar because:a vector has direction whereas a scalar does not have direction
- 2Chen left home and went for a jog. He jogged 8.0 km [W], then 5.0 km [E] followed by 3.0 km [W]. What is Chen's final position from home?6.0 km [W]
- 3A runner makes 2 laps around a circular track, ending at the same point she started from. What two things will equal zero?displacement and average velocity
- 4A car is traveling south while slowing down as it approaches a stop sign. The directions associated with the objects velocity and acceleration, respectively, are[S], [N]
- 5Which of the following statements about motion graphs is incorrect? a. The slope of a velocity-time graph gives acceleration. b. The area under a velocity-time graph gives displacement. c. The area under a position-time graph gives velocity.c
- 6A boy pulls on a wagon with a force of 100 N [E]. The wagon pulls on the boy with a force of100 N [W]
- 7If a car is traveling north at constant velocity, the net force acting on the car is:zero because velocity is constant
- 8The acceleration of an object is always in the directionof the net force
- 9Which of the following statements is always true? a. There is an unbalanced force on an object if it is in motion. b. An object in motion has a tendency to stay in motion. c. There are no forces acting on an object if it is at rest.b
- 10If you were to increase the mass of an object in motion, the net force required to keep it moving at the same rate of acceleration wouldincrease
- 11What is happening in this position-time graph?The object is moving north with decreasing velocity
- 12A motorcycle accelerates from rest to a velocity of 32 m/s [forward]. If its rate of acceleration was 7 m/s2 [forward], how long did it take him to reach this velocity?a = v - v / t
7 = (32 - 0) / t
t = 4.6 s - 13In a period of 2.0 h, a sailboat travels 15 km [E] and then 11 km [W]. What is the boat's total distance travelled?15km + 11km = 26km
- 14In a period of 2.0 h, a sailboat travels 15 km [E] and then 11 km [W]. What is the boat's total displacement?+15km - 11km = 4 km [E]
- 15In a period of 2.0 h, a sailboat travels 15 km [E] and then 11 km [W]. What is the boat's average speed (in km/h)v = d/t
v = 26/2
v = 13 km/h - 16Describe the motion of the object from 0 to 15 suniform velocity to the east
- 17Describe the motion of the object from 15 - 30 s.object is stopped
- 18Describe the motion of the object from 30 s to 40 sUniform velocity to the west
- 19What is the velocity of the object at 10 s?slope of line (rise over run)
(4 - 0) / (15 - 0) = 0.3 m/s [E] - 20The term "weight" in physics means the same thing asforce of gravity
- 21A ball is thrown straight up, reaches a maximum height, then falls to its initial height. What can be said about the direction of the velocity and acceleration of the ball as it is going up?velocity is upwards, acceleration is downwards (gravity)
- 22A ball is thrown at an angle 37* to the horizontal. What happens to the magnitude of the ball's vertical acceleration during the total time interval that the ball is in the air?acceleration stays the same (gravity is always -9.8m/s2 on Earth)
- 23What is the vertical speed of a ball during two dimensional projectile flight at its peak?0 m/s
- 24What is an example of projectile motion?a bullet fired from a gun
- 25A glider takes off horizontally at 10 m/s from a 45 m cliff, what is the maximum height the glider reaches?45 m because it is launched horizontally so the height of the cliff is the highest the glider will be
- 26A marble is shot from the ground level and follows a parabolic path shown. Air resistance is negligible. Point B is the highest point on the path. What is the direction of the velocity, if any of the marble at point B?to the right
- 27A marble is shot from the ground level and follows a parabolic path shown. Air resistance is negligible. Point B is the highest point on the path. Which of the following indicates the direction of the net acceleration of the marble at point C?downwards
- 28At what angle above the horizon would a projectile achieve the longest range?45*
- 29At what angle above the horizon would a projectile achieve the greatest height?90*
- 30What is constant for all projectilesvertical acceleration (gravity)
&
horizontal velocity - 31A box with a mass of 9.5 kg is sitting on the floor. The magnitude of the normal force acting on the mass:9.5 x 9.8 = 93 N
- 32A United Airlines jet is flying at 300 km/hr, while an Air France Concorde is speeding along at 1200 km/hr. Both airplanes are flying at the same altitude. If each aircraft pushes a package out the door, which package will hit the earth first? (Ignore air resistance)They will both hit the ground at the same time
- 33What is the velocity at the the peak of the motion of an object that is thrown directly upwards?0 m/s
- 34A 45.0 kg person steps on a scale in an elevator. The scale reads 460 N as the elevator accelerates. What direction is the elevator accelerating?Fg = 45 x 9.8 = 441 N
460 N > 441 N so person feels heavier so the elevator is accelerating upwards - 35If you push on a railroad boxcar with a force of 300 N and it doesn't move, you can conclude thatThe boxcar is applying a force of 300 N in the opposite direction
- 36A truck is using a hook to tow a car whose mass is one quarter that of the truck. If the force exerted by the truck on the car is 600 N, then the force exerted by the car on the truck is600 N
- 37The mass of an object on earth is 5.0 kg. On the moon, where the gravitational acceleration is 1.62 m/s2, what is the mass of the object?5 kg, mass doesn't change
- 38A circular race track has a radius of 159 m. If the centripetal force acting on a 65.0 kg cyclist is 4.16 N, how long does it take to complete one lap around the track?Fc = mv2/r
v = 3.2 m/s
v = 2(pi)r / T
T = 313 s - 39At what speed can a car safely negotiate a frictionless curve of radius 115 m if the road is banked at an angle of 35.0*?tan(theta) = v2/ gr
tan(35) = v2 / (9.8*115)
v = 28.1 m/s