Forces Review Which of the following is the cause of an acceleration or a change in an object’s motion? speed inertia force velocity 0% ve lo cit y e 0% fo rc a 0% in er ti 0% sp ee d 1. 2. 3. 4. Which of the following forces is an example of a field force? gravitational force frictional force normal force tension m n 0% te ns io al fo rc e 0% no r fri ct io na lf or fo rc e na l tio vit a 0% ce 0% gr a 1. 2. 3. 4. A cart is pushed with an acceleration of 2 m/s2. If µ = 0.5, what does the net force equal? FA FFr FA – FN FA – FFr 0 –F 0% 0 FN – FA 0% Fr 0% FA 0% FF r 0% FA 1. 2. 3. 4. 5. An army ranger is lifted by a cable to a helicopter at a constant velocity? FT Fg FT – Fg Fg – FT 0 –F Fg FT 0% 0 0% T 0% –F g 0% Fg 0% FT 1. 2. 3. 4. 5. A bike is coasting to a stop. What is the net force equal to? Gravitational Force Zero Frictional Force Normal Force 0% 0% ce al Fo r m No r lF or c e Ze ro 0% Fr ict io na ta t io na lF or c e 0% Gr av i 1. 2. 3. 4. Which of the following is the tendency of an object to maintain its state of motion? acceleration inertia force velocity 0% ve lo cit y e 0% fo rc a 0% in er ti tio n 0% ac ce le ra 1. 2. 3. 4. An object with a mass of 100kg has what weight in Newtons? 25% 25% 50 0 25% 0 25% 98 0 9.8 980 0 500 9. 8 1. 2. 3. 4. With a constant applied force, mass is directly proportional to acceleration. This statement describes which of Newton’s Laws? 0% 0% b. .. ea th of No ne 0% 3r d 0% 2n d 1st 2nd 3rd None of the above 1s t 1. 2. 3. 4. If a nonzero net force is acting on an object, then the object is definitely 1. at rest. 2. moving with a constant velocity. 3. being accelerated. 4. losing mass. as s. 0% lo s in gm te d. 0% cc el er a ga be in a co n sta n at wi th ng ov i m 0% t. .. re st . 0% Which are simultaneously equal but opposite forces resulting from the interaction of two objects? 1. net external forces 2. field forces 3. gravitational forces 4. action-reaction pairs pa io n re ac t ac t io n- tio vit a 0% irs fo rc es 0% na l fie ld fo rc es 0% gr a ne te xt er na lf or ce s 0% What is not true regarding action reaction forces? on ct Th ey a tru e. 0% ar e Al l sa m th e on ct Th ey a 0% di f fe re nt e t io n ica ap pl an re Th ey a 0% ob ... .. 0% ob . .. 1. They are an application of Newton’s 3rd Law. 2. They act on the same object. 3. They act on different objects. 4. All are true. The magnitude of the force of gravity acting on an object is frictional force. weight. inertia. mass. as s. 0% m a. 0% in er ti ei gh t. 0% w io na lf or ce . 0% fri ct 1. 2. 3. 4. In the terminology “a 500-N block”, the 500-N refers most specifically to the block's: 0% ei gh bo ve . t. 0% ea th of No ne e. 0% fo rc as s. 0% w mass. force. weight. None of the above. m 1. 2. 3. 4. It is generally easier to overcome friction when an object is moving than at rest because … 0% 0% he n an o. .. ob .. . ea se sw he n de cr in cr Fg 0% an ha n ea se sw gr ea te rt is µs µk is gr ea te rt ha n µs µk 0% Fg 1. µk is greater than µs 2. µs is greater than µk 3. Fg increases when an object moves 4. Fg decreases when an object moves As a car coasts on a level road yet slows down, the net force acting on the tires is: fo r al fo rc e m al no r th e no rm th e o lt eq ua 0% ze ro . 0% .. .. . al m no r th e n gr ea te rt ha 0% ce . .. 0% tim es t 1. greater than the normal force times the coefficient of static friction. 2. equal to the normal force times the coefficient of static friction. 3. the normal force times the coefficient of kinetic friction. 4. zero. If an object changes its direction of motion: 0% ... ha ve he ce m us t of t sp ee d 0% be en ob je ct ob je ct . .. .. . 0% he th e in th e th e m as er ti a so ft of t he ob je ct h. . 0% af or 1. the mass of the object had to change. 2. the inertia of the object had to change. 3. the speed of the object stays the same. 4. a force must have been applied to the object. If no forces are acting on an object, its motion will: 1. continue in the same direction with the same speed. 2. slow down and eventually stop. 3. continue at the same speed but could change direction. 4. continue in the same direction but could change speed. 0% 0% 0% ue co n tin ue in at di r.. . th e th e sa m sa m e e sp ... l.. ev en tu al tin co n w slo co n tin ue do w n in an d th e sa m e di r.. . . 0% If the net force is negative and the speed is positive: ed i im m sp ee d w ill st a ill w sp ee d th e 0% at e. . ... yt cr ea se in ill w sp ee d th e 0% he .. . de cr ea se ill w sp ee d th e 0% ov .. 0% th e 1. the speed will decrease over time. 2. the speed will increase over time. 3. the speed will stay the same. 4. the speed will immediately drop to zero. Which of the following will not change as you increase the slope of a ramp? 1. Normal Force 2. Fgx 3. coefficient of friction 4. Fgy 0% Fg y of fri ct io en t co ef fic i No r 0% n Fg x 0% m al Fo r ce 0% Which of the following about an object on a ramp will increase if you decrease the slope of a ramp? lF io na ta t Gr av i 0% fF r ic t io n e or c or c lF 0% Fg x 0% e 0% Co ef fic ie nt o Frictional Force Gravitational Force Fgx Coefficient of Friction Fr ict io na 1. 2. 3. 4. What happens to the normal force as the angle of a ramp increases? 0% co .. . ns re m m al fo rc e No r No r m al fo rc e de cr in cr al fo rc e m No r 0% ea se s ea se s 0% ai 1. Normal force increases 2. Normal force decreases 3. Normal force remains constant What happens to the coefficient of friction as the angle of a ramp increases? 1. µ increases 2. µ decreases 3. µ remains constant 0% ns c de cr ea s on st an t es 0% µ re m ai µ µ in cr ea se s 0% The gravitational force on an object is 98N. What is the object’s mass in kg? 98 9.8 980 10 0% 10 0% 98 0 0% 9. 8 0% 98 1. 2. 3. 4. Fg Fg sin10 Fg cos10 Fg tan10 FFr 0% FF r an 10 0% Fg t Fg c Fg s 0% os 10 0% in 10 0% Fg 1. 2. 3. 4. 5. A 1000kg car is at rest on a slope of angle 10o. What equals the normal force? A 1000kg car is at rest on a slope of angle 10o. What equals the frictional force? Fg Fg sin10 Fg cos10 Fg tan10 FFr 0% FF r an 10 0% Fg t Fg c Fg s 0% os 10 0% in 10 0% Fg 1. 2. 3. 4. 5.