EXAM 1

1) When a ball thrown straight upwards reaches the very top of its path, its acceleration is 1) A) 10 ms^2 B) 5 ms^2 C) zero. D) none of the above

A

19) Science later greatly advanced when Galileo favored A) experiment over philosophical discussions. B) nonmathematical thinking. C) philosophical discussions over experiment. D) none of the above

A

2) Pseudoscience is best characterized as being A) fake. B) new age. C) an alternate view to be taken seriously. D) all of the above

A

22) The most basic of the sciences of physics, chemistry, and biology is A) physics. B) biology. C) chemistry. D) none of die above

A

24) Inertia is defined as a A) property of matter. B) force. C) change in motion. D) none of the above

A

38) The force of friction on a sliding object is 10 N. The applied force needed to maintain a constant velocity is A) 10 N. B) less than 10 N. C) more than 10 N.

A

47) An object falls freely from rest on a planet where the acceleration due to gravity is 20 m/s^. After 5 seconds, the object will have a speed of A) 100 m/s. B) 10 m/s. C) 50 m/s. D) 20 m/s. E) 5 m/s. '

A

12) The speedometer of an automobile reads A) average speed. B) instantaneous speed. C) accelerated speed.

B

18) Two vehicles with equal magnitudes of momentum traveling at right angles to each other undergo an inelastic collision. The combined wreck moves in a direction A) at some angle other than 45 degrees. B) at 45 degrees to the direction of either car before collision. C) parallel to either of the cars before collision.

B

20) Weigh yourself on a weighing scale and the scale shows your normal weight. If you carefully stand on tiptoes, the scale reading will be A) slightly more. B) no different. C) slightly less. D) about half as much.

B

25) One end of a rope is pulled with 100 N, while the opposite end also is pulled with 100 N. The tension in the rope is A) 200 N. B) 100 N. C)50N. D)0N.

B

26) A Mack truck and a Volkswagen traveling at the same speed have a head-on collision. The vehicle that undergoes the greatest change in velocity will be the A) Mack truck. B) Volkswagen. C) same for both.

B

32) The time it takes a car to attain a speed of 30 m/s when accelerating from rest at 2 m/s2 is A) 30 s. B) 15 s. C) 2 s. D) 60 s.

B

39) A rock weighs 30 N on Earth and another rock weighs 30 N on the Moon. Which rock has the greater mass? A) They have the same mass. B) the one on the Moon C) the one on Earth D) not enough information

B

40) A light woman and a heavy man jump from an airplane at the same time and open their same-size parachutes at the same time. Which person will get to a state of zero acceleration first? A) The heavy man B) The light woman C) Both should arrive at the same time. D) not enough information

B

44) A car by itself is capable of a certain maximum acceleration. When it tows a twice-as-massive car, its maximum acceleration is A) one half. B) one third. C) one fourth. D) the same. E) none of these

B

8) If no external forces act on a moving object, it will 8) A) come to an abrupt halt. B) continue moving at the same speed. C) move slower and slower until it finally stops. D) none of the above

B

10) Nellie pulls with a force of 50 N on a horizontal rope tied to a tree at rest. The net force on the rope A-l is A) 50 N and rope tension is also 50 N. B) zero and rope tension is also zero. C) zero and rope tension is 50 N. D) 50 N and rope tension is 0 N.

C

15) Jogging Jake runs at 4 m/s along a train flatcar that moves at 10 m/s in the same direction. Jake's speed relative to the ground is A) 6 m/s. B) 10 m/s. C) 14 m/s. D) none of the above

C

27) Which of the following is a scientific statement? A) there are parts of the universe that will never be discovered by humans B) there are things we will never know about C) candy Bon Bons contain no sugar D) matter is filled with undetectable particles E) none of the above

C

28) If gravity between the Sim and Earth suddenly vanished, Earth would continue moving in A) an outward spiral path. B) a curved path. C) a straight-line path . D) an inward spiral path.

C

3) The winner in a tug-of-war exerts the greatest force on A) the opponent. B) his or her end of the rope. C) the ground.

C

30) Which has the greater momentum when moving? A) a container ship B) a bullet C) either of these depending on speed

C

36) An object covers a distance of 8 meters in the first second of travel, another 8 meters during the next= second, and 8 meters again during the third second. Its acceleration is A) 5 m/s2. B) 24 m/s2. C) 0 m/s2. D) none

C

37) The airspeed of an airplane is 200 km/h. When it is caught in a 200-km/h crosswind, its speed across the ground below is A) 400 km/h. B) 1600 km/h. C) 283 km/h. D) 200 km/h. E) 0 km/h.

C

41) A force is a vector quantity because it has both A) speed and direction. C) magnitude and direction. 41) B) mass and velocity. D) action and reaction counterparts.

C

42) The speed of a 4-kg ball with a momentum of 12 kg m/s is A) 12 m/s. B) 48 m/s. C) 3 m/s. D) 4 m/s. E) none of the above

C

43) The amount of force needed to sustain motion of a rock in outer space is A) a force equal to its weight. B) a force less than its weight if friction is absent. C) none of these

C

46) A tree stump is pulled northward by a 10-N force at the same time a 25-N force pulls it southward. The resultant force has a magnitude of A) 25 N. B) 0 N. C) 15 N. D)150N.

C

50) If a rocket initially at rest accelerates at a rate of 50 m/s^ for one minute, its speed will be A) 500 m/s. B) 50 m/s. C) 3000 m/s. D) 3600 m/s.

C

9) When a karate chop breaks a board with a 3000-N blow, the amount of force that acts on the hand is A) 6000 N. B) 1500 N. Q3000N. D) zero.

C

5) A 5-kg fish swimming at 1 m/s swallows an absent-minded 1-kg fish at rest. The speed of the larger fish after lunch is A) 6/5 m/s. B) 1 m/s. C) 5/6 m/s. D) 2/5 m/s. E) 1/2 m/s.

C 1/ms*5kg=(5kg+1kg)*(X m/s)

31) If a stone falls to the bottom of a mineshaft in 6 seconds, then the depth of the shaft is about A) 120 m. B) more than 200 m. C) 180 m. D) 60 m.

C(.5xgxt^2)

11) A theory in the field of science is A) unchangeable. B) less than a fact. C) an educated guess. D) a synthesis of a large body of well-tested knowledge.

D

14) Compared to a 1-kg block of solid iron, a 2-kg block of solid iron has twice as much A) mass. B) volume. C) inertia. D) all of the above E) none of the above

D

16) If a car increases its velocity from zero to 60 m/s in 10 seconds, its acceleration is A) 3 m/s^. B) 60 m/s^. C) 600 m/s^. D) 6 m/s^.

D

17) A river 100 m wide flows due south at 1 m/s. A boat that goes 1 m/s relative to the water leaves the west bank. To land at a point due east of its starting point, the boat must be pointed A) northeast. B) southeast. C) east. D) nowhere-it can't be done.

D

21) A 1-kg mass at the Earth's surface weighs A) 1N. B) 12 N. C) 5 N. D) 1ON.

D

33) A 300-kg bear grasping a the tree and the bear is A) more than 3000 N. B) 300 N. C) 30 N. D)3000 N.

D

34) Neglecting air resistance, a ball projected straight upward so it remains in the air for 10 seconds needs an initial speed of A) 110 m/s. B) 60 m/s. C) 100 m/s. D) 50 m/s. E) 80 m/s.

D

45) A 1000-kg automobile enters a freeway on-ramp at 20 m/s and accelerates uniformly up to 40 m/s in a time of 10 seconds. How far does the automobile travel during that time? A) 100 m B) 200 m C) 400 m D) 300 m E) none of the above

D

48) Science is a body of knowledge that A) condenses knowledge into testable laws. B) describes order in nature. C) is an ongoing human activity. D) all of the above E) none of the above

D

7) Padded dashboards in cars are safer in an accident than non-padded ones because passengers hitting the dashboard encounter A) decreased impulse. B) shorter time of contact. C) increased momentum. D) lengthened time of contact.

D

35) A 2-kg rifle that is suspended by strings fires a 0.01-kg bullet at 200 m/s. The recoil velocity of the rifle is about A) 0.1 m/s. B) 0.001 m/s. C) 0.01 m/s. D) 1 m/s. E) none of these

D (.01X200)/2

13) Scotty Skydiver of mass 100 kg experiences air resistance of 500 N, and an acceleration of about A) greater than 0.5 g. B) 0.3 g. C) 0.4 g. D) 0.5 g. E) 0.2 g.

D (100kg*10g)/500

29) A jumbo jet has a mass of 100,000 kg. The thrust for each of its four engines is 50,000 N. What is the jet's acceleration when taking off? A) 1 m/s2 B) 4 m/s2 C) 0.25 m/s2 D) 2 m/s2 E) none of the above

D (50,000*4)/100,000

23) The resultant of a 40-N force at right angles to a 30-N force is A) greater than 50 N. B) 40 N. C) 30 N. D) 50 N.

D (squar root(40^2+30^2))=c)

49) A motorcycle of mass 100 kilograms slowly rolls off the edge of a cliff and falls for three seconds before reaching the bottom of a gully. Its momentum upon hitting the ground is A) 2,000 kg m/s. B) 4,000 kg m/s. C) 9,000 kgm/. D) 1,000 kg m/s. E) 3,000 kg m/s.

E

6) The average braking force of a 1000-kg car moving at 10 m/s braking to a stop in 5 s is A) 5000 N. B) 4000 N. C) 1000N. D)3000N. E) 2000 N.

E 1000kg*10m/s=x*5sec

4) As a ball falls, the action force is the Earth's pull on the ball. The reaction force is the A) acceleration of the ball. B) ball's pull on Earth. C) air resistance acting against the ball. D) none of the above

c