i hate physics part 1

Significant Figures: Write 290,000,000 with 3 significant figures

2.90 times 10 ^ 8

In a friendly game of handball, you hit the ball essentially at ground level and send it toward the wall with a speed of 16 m/s at an angle of 37 degree above the horizontal. (a) What amount of time is required for the ball to reach the wall if it is 3.3m away? (b) How high is the ball when it hits the wall?

( A) t= d/Vo (cos theta) = 3.3/16cos 37 = .26 s (B) h= ( Vo sin theta) (t)- (1/2 g t^2) = (16sin37) 26- (1/2 time 9.81 times .26^2) = 2.2m

You shoot an arrow into the air. Two seconds later (2.00s) the arrow has gone straight upward to a height of 30.0m above its launch point. (A) what was the arrow's initial speed? (B) How long did it take for the arrow to first reach a height 15.0m above its launch point?

(A) v0= x-(1/2) (a)(t^2) / t = 24.8 (B) T=quadratic formula a= 9.81/2 b= 24.8 c= 15 = .702s

A jogger runs with a speed of 3.45 m/s in a direction 35.0 degrees above the x axis. Find the x and y components of the jogger's velocity. Calculate the components of the velocity for the case where the speed of the jogger in part A is halved?

(A) = Vx= 3.45cos35= 2.83 m/s Vy= 3.45sin35= 1.98m/s (B) (1/2 times 3.25) ( cos 35) = 1.33 m/s (1/2 times 3.25) ( sin 35)= .932

A 3.50 kg block on a smooth tabletop is attached by a string to a hanging block of mass 2.80 kg as shown in figure 6-55. The blocks are released from rest and allowed to move freely. a) Is the tension in the string greater than, less than, or equal to the weight of the hanging mass? b) find the acceleration of the blocks and c) the tension in the string

(A) Less than (B) a = ( m2/m1+m2) (g) = 2.8/3.5+2.80 (9.81)= 4.36 m/s^2 (C) T = m1 a= ( 3.50)(4.36) = 15.3N

The pulley system shown is used to lift an m = 67 kg crate. Note that one chain connects the upper pulley to the ceiling and a second chain connects the lower pulley to the crate. Assume the masses of the chains and pulleys are negligible. a) Determine the Force required to life the crate with constant speed b) Determine the tension in the upper chain c) Determine the tension in the lower chain

(a) F=1/2 ( lower crate mass) ( g) = 1/2(67)(9.81) = 329 N downward (B) = 2 time F = 2 time 329 = 660 N C= mg = 67 times 9.81 = 657 N

A mug rests on an inclined surface, as shown in figure 6-35. (a) What is the magnitude of the frictional force exerted on the mug? (b) What is the minimum coefficient of static friction required to keep the mug from sliding? mass of the mug is 0.27 kg, angle of the surface is 14 degrees

(a) Fs=mgsin theta= (.27)(9.81)(sin 14) =.64 N (B) coefficient = Fs/N = Fs/ mgcostheta = .64/ (.27)(9.81) cos 14 = .25

How many messages can you send per week if you send 1 message every 9 seconds?

67200

Vector A points in the negative x direction and has a magnitude of 23 units. The vector B points in the positive y direction. Find the magnitude of B if A + B has a magnitude of 35 units.

B= the square root of (35^2)- (-23^2) =39units

An archer shoots an arrow horizontally at a target 15m away. The arrow is aimed directly at the center of the target, but it hits 54cm lower. What was the initial speed of the arrow?

CHANGE CM TO M average time= the square root of 2 time delta y / g = square root of 2 times .54/ 9.81= .332 sec v= average x/ average time = 15m/ .332 =45m/s

After a skiing accident, your leg is in a cast and supported in a traction device, as shown in Figure 6-43. Find the magnitude of the force F⃗ exerted by the leg on the small pulley. (By Newton's third law, the small pulley exerts an equal and opposite force on the leg.) Let the mass m be 2.27 kg.

F=2 mg cos theta = 2(2.27)(9.81)(cos 30) = 38.6N

When you take your 1900kg car out for a spin you go around a corner of radius 53m with a speed of 13 m/s. The coefficient of static friction between the car and the road is 0.88. Assuming your car doesn't skid, what is the force exerted on it by static friction?

F=mv^2/r = (1900)(13)/ (53) = 6060 N

When a 9.48 kg mass is placed on top of a vertical spring, the spring compresses 4.15 cm. Find the force constant of the spring

K= -F/x = mg/x = (9.48)(9.81)/ (.0415) = 2241 N/m

Dimensional Analysis: V^2 = 2ax^2 . Find P

L^2=L^p+1 p=1

Two blocks are connected by a string shown in figure 6-44. The smooth inclined surface makes an angle of 42 degrees with the horizontal, and the block on the incline has a mass of 6.7kg. Find the mass of the hanging block that will cause the system to be in equilibrium

M=m sin theta = 6.7 (sin 42) = 4.5 kg

A particle undergoes a displacement r of magnitude 54m in a direction 42 degrees below the x axis. Express r in terms of the unit vectors x and y

Rx= 54m cos (-42)= 40m Ry+ 54m sin(-42) = 36m R= ( 40 m) X+(-36)Y

As you ride on a ferris wheel, your apparent weight is different at the top than at the bottom. Calculate your apparent weight at the top and bottom of the ferris wheel, given that the radius of the ferris wheel is 7.2m, it completes one revolution every 28s, and your mass is 53kg. Consider centrifugal acceleration at the top and bottom!

V= 2 pie r/ T = 2 pie time 7.2/ 28 1.6m/s N top= m(g-V^2/r) = 508N Nbottom= m ( g+v^2/r) =532

A soccer ball is kicked with a speed of 18.0 m/s at an angle of 32.5 degrees above the horizontal. If the ball lands at the same level from which it was kicked, for what amount of time was it in the air? Express your answer using three significant figures

Voy= Vo sin theta=(18m/s) sin 32.5= 9.67m/s t= Vy- Voy/-g = -9.67-(9.67)/-9.81 = 1.97 s

A diver runs horizontally off the end of a diving board with an initial speed of 1.85m/s. If the diving board is 3.0m above the water, what is the divers speed just before she enters the water?

Vy^2= Voy^2 -2gdeltay= 0-2(9.81)(0-3) = 58.9 m^2/S^2 V= sqaure root of Vx^2 + V^2y = 7.89m/s

New York is roughly 3000 miles away from Seattle. When it is 10am in Seattle it is 1pm in New York. a) what is the rotational speed of the earth? b) what is the circumference of the earth? c) What is the radius of the earth? Don't forget what Order of Magnitude Means

a) v=d/t = 10^3 b) circumference =vt = 10^4 C)r= circumference/ 2 pie = 10^ 3

Find the acceleration of the masses shown in figure 6-53, given that m1= 1.0kg , m2= 2.0kg, and m3= 3.0kg

a= (m3/ m1+m2+m3) (9.81) = ( 3/6)(9.81) = 1.4 m/s^2

Landing with a speed of 81.9m/s, and traveling due south, a jet comes to rest in 949m. Assuming the jet slows with constant acceleration, find the magnitude and direction of its acceleration.

a= v^2 -vo^2/ 2 delta x = 0^2-81.9^2/ 2 ( 949) = 3.53 m/s^2 to the north

A Meteorite Strikes On October 9, 1992, a 27-pound meteorite struck a car in Peekskill, NY, leaving a dent 22 cm deep in the trunk. If the meteorite struck the car with a speed of 130 m/s , what was the magnitude of its deceleration, assuming it to be constant?

a= v^2 -vo^2/ 2 delta x =0^2-130^2/2( .22) = 3.8 time 10 to the eighth

A 747 airliner reaches its takeoff speed of 173mi/h in 35.2 s. What is the magnitude of its average acceleration?

average acceleration= average speed/ average time 173-0/ 35.2 = 2.20 m/s^2

On your wedding day you leave for the church 35.0 minutes before the ceremony is to begin, which should be plenty of time since the church is only 10.0 miles away. On the way, however, you have to make an unanticipated stop for construction work on the road. As a result, your average speed for the first 20.0 minutes is only 5.0 mi/h . What average speed do you need for the rest of the trip to get you to the church on time?

d1=(v1)(t1 change minutes to hours)= 1.67 miles d2= d final - d1= 8.33 average speed= d2/35min-t1 in hours) = 35 miles/ hour

You jog at 9.5 km/h for 7.0 km, then you jump into a car and drive an additional 16 km. With what average speed must you drive your car if your average speed for the entire 23 km is to be 22 km/h?

delta t=d/s time elapsed while jogging = d1/v1 t elapsed while in car= delta t- time elapsed while jogging speed= d2/t elapsed while in car = 52 km/h

Does an odometer measure distance or displacement?

distance

Does projectiles for which the air resistance is non-negligible, such as a bullet firing from a rifle, have maximum range when the launch angle is greater than , less than or equal to 45 degrees?

less than 45

Can a vector have a component that is greater than its magnitude?

no

Can a vector with 0 magnitude have one or more non-zero components?

no

Is it possible for a car to circle a race track at constant velocity at constant speed?

no

Driving down the highway, you find yourself behind a heavily loaded tomato truck. you follow close behind the truck, keeping the same speed. suddenly a tomato falls from the back of the truck. will the tomato hit your car or land on the ground assuming you continue moving at the same speed and direction?

the tomato will land on the ground in front of you

A particle undergoes a displacement r of magnitude 54m in a direction 42 degrees below the x axis. Express r in terms of the unit vectors x and y.

rx= (54) =(cos -42) = 40m ry= 54 sin -42= -36m r= (40m)x+(-36m) y

You are driving up an inclined road and after 1.2 miles your elevation increases by 530 ft. What is the angle of the road horizontal?

sin theta = y/s theta = sin^-1 ( y/s) theta= sin^-1 (530/ 1.2 time 5280 to make it in ft) = 4.8 degrees

Running with an initial velocity of +11.3 m/s, a horse has an average acceleration of -1.81 m/s2. How much time does it take for the horse to decrease its velocity to +6.9 m/s? Express your answer using two significant figures.

t= v-vo/ a = 6.9-11.3/-1.81 =2.4 s