امتحان جامد هيك

A furlong is a distance of 220 yards. A fortnight is a time period of two weeks. A racehorse is running at a speed of 5.00 yards per second. What is his speed in furlongs per fortnight?

• a) 27 500 furlongs/fortnight

• b) 13 700 furlongs/fortnight

• c) 6 220 furlongs/fortnight

• d) 2 750 furlongs/fortnight

The word 'sI' in SI units stands for

• Standard International

• System de International

• System Internationalle

• Standard Integrated

A 2 000-kg sailboat experiences an eastward force of 3 000 N by the ocean tide and a wind force against its sails with the magnitude of 6 000 N directed toward the northwest (45° N of W). What is the direction of the resultant acceleration?

• a. 60° N of E

• b. 30° N of W

• c. 30° N of E

• d. 74° N of W

A thrown stone hits a window but doesn't break it. Instead, it reverses direction and ends up on the ground below the window. In this case, we know

• a. the force of the stone on the glass > the force of the glass on the stone

• . b. the force of the stone on the glass = the force of the glass on the stone.

• c. the force of the stone on the glass < the force of the glass on the stone

• d. the stone didn't slow down as it broke the glass.

. A baseball batter hits an incoming 40-m/s fastball. The ball leaves the bat at 50 m/s after a ball-on-bat contact time of 0.030 s. What is the force exerted on the 0.15-kg baseball?

• a. 450 N

• b. 250 N

• c. 90 N

• d. 50 N

An object moves in a circle. If the mass is tripled, the speed halved, and the radius unchanged, then the magnitude of the centripetal force must be multiplied by a factor of:

• A. 3/2

• B. 3/4

• C. 9/4

• D. 6

Find the tensions in the cables C and D. Set up your x and y equations where indicated and solve.

• (C = 192 N, D = 285 N)

• (C = 179 N, D = 265 N)

• (C = 180 N, D = 367 N)

• (C = 186N, D = 265 N)

• 3m/s2

• 2 m/s2

• 7 m/s2

• 5 m/s2

• 4 m/s2

An 800-N billboard worker stands on a 4.0-m scaffold weighing 500 N and supported by vertical ropes at each end. How far would the worker stand from one of the supporting ropes to produce a tension of 550 N in that rope?

• a. 1.4 m

• b. 2.0 m

• c. 2.5 m

• d. 2.7 m

An 80-kg man is one fourth of the way up a 10-m ladder that is resting against a smooth, frictionless wall. If the ladder has a mass of 20 kg and it makes an angle of 60° with the ground, find the force of friction of the ground on the foot of the ladder.

• a. 7.8 x 102 N

• b. 2.0 x 102 N

• c. 50 N

• d. 1.7 x 102 N