Math and Physics: Week 1-3 Flashcards
A man walks 30 m east and then 40 m north. What is the difference between his traveled distance and his displacement?
A. 0 m
B. 20 m
C. 50 m
D. 70 m
20 m
A 1000 kg rocket ship, travelling at 100 m/s, is acted upon by an average for of 20 kN applied in the direction of its motion for 8 s. What is the change in velocity of the rocket?
A. 160 m/s
B. 260 m/s
C. 160,000 m/s
D. 260,000 m/s
160 m/s
(check kaplan for explanation)
A car is traveling at 40 km/hr and the driver puts on the brakes, bringing the car to rest in a time of 6 s. What is the magnitude of the average acceleration of the car?
A. 240 km/hr^2
B. 12,000 km/hr^2
C. 24,000 km/hr^2
D. 30,000 km/hr^2
24,000 km/hr^2
An elevator is designed to carry a maximum weight of 9800 N, to move upward at a speed of 5 m/s. What is the relationship between the maximum tension in the elevator cable and the maximum weight of the elevator in movement?
The cable tension will be greater than 9800 N, because at 9800 N or less tension is considered negligible and the elevator can move.
A student must life a mass of 4 kg a distance of 0.5 m. The ambient temperature is 298 K and the student must lift the mass in 30 s. Which of the following values is not needed to calculate power?
A. Mass.
B. Distance.
C. Temperature.
D. Time.
Temperature
Power = Watts = kg*m^2/s^3
A firefighter jumps horizontally from a burning building with an initial speed of 1.5 m/s. At what time is the angle between his velocity and acceleration vectors the greatest?
Maximum angle occur the instant he jumps.
A 10 kg wagon rests on an inclined plane. The plane makes an angle of 30 degrees with the horizontal. Approximately how large is the force required to keep the wagon from sliding down the plane?
A. 10 N
B. 49 N
C. 85 N
D. 98 N
49 N
(10 kg) * (9.8 ms^2) * (Sin 30) = 49 N.
Which of the following expressions correctly illustrates the SI base units for each of the variables in the formula below?
mdeltaV = Fdelta T
A. lbmph = ft lb * s
B. kg *(m/s) = N *S
C. kg(m/s) = (kgm/s^2) * s
D. g * (m/s) = (g*m/s^2) * s
C
Which of the following quantities is not a vector?
A. Velocity.
B. Force.
C. Displacement.
D. Distance.
Distance.
A 30 kg girl sits on a seesaw at a distance of 2 m from the fulcrum. Where must her father sit to balance the seesaw if he has a mass of 90 kg?
A. 67 cm from the girl.
B. 67 cm from the fulcrum.
C. 133 cm from the girl.
D. 267 cm from the fulcrum.
67 cm from the fulcrum.
A physics major builds a potato gun and tests it in an open field. He launches a potato with a velocity of 12 m/s at an angle of 30 degrees. The potato is found 60 m from the launch site. Which of the following represents the maximum height achieved by the potato?
A. 0.3 m
B. 1.8 m
C. 5 m
D. 18 m
B. 1.8 m
A rock (m = 2 kg) Is shot up vertically at the same time that a ball (m = 0.5 kg) is projected horizontally. If both start from the same height:
A. The rock and ball will reach the ground at the same time.
B. The rock will reach the ground first.
C. The ball will reach the ground first.
The ball will reach the ground first.
Because the rocks begin with an upward velocity, it will take more time to reach a maximum height before falling.
Centrifugal force is an apparent outward force during circular motion. It has been described as a reaction force according to Newton’s third law. What of the following statements is true?
A. Centrifugal force exists only for uniform circular motion.
B. Centrifugal force exists only when tension or normal force provides centripetal acceleration.
C. Centrifugal force always acts antiparallel to the centripetal force vector.
D. Centrifugal force is a result of repulsive electrostatic interactions.
C - Centrifugal force always acts antiparallel to the centripetal force vector.
Which of the following statements is true of movement on a plane with friction?
- Acceleration is a function of applied force only.
- More force is needed to accelerate a stationary object than an identical moving object.
- The force of friction is independent of the mass of objects.
Only 2 - must overcome static friction, which is greater than kinetic friction.
