physics quarterly calculations
During a hockey game, a puck is given an initial speed of 10 m/s. It slides 50 m on the horizontal ice before it stops due to friction. What is the coefficient of kinetic friction between the puck and the ice?
0.10
A boy throws a rock with an initial velocity of 10 m/s from a bridge. How long does it take for the rock to reach the maximum height of its trajectory if air resistance is small and g=9.8 m/s^2?
0.160
A 40 kg object is being pushed along a surface at a constant velocity by a force of 80 N. What is the coefficient of kinetic friction between the object and the surface?
0.2
An object traveling at 16 m/s enters a frictional area. It comes to rest after a time of 4 s. The coefficient of friction of the frictional area is
0.4
A 45 kg person steps on a scale in an elevator. The scale reads 460N, what is the magnitude if the acceleration of the elevator?
0.422
In the figure above, the coefficient of kinetic friction between the block of mass M and the table is 0.5. If the pulley is massless and frictionless, determine the acceleration of the blocks if they released from rest. (PULLEY TABLE)
0.5g
A 50 kg mass is placed on an inclined plane that makes an angle of 37 with the horizontal. When released, the mass remains motionless. The coefficient of static friction between the mass and the plane is at least
0.8
If a net force accelerates a 4.5 kg tool at 40, what acceleration would that same net force give to an 18 kg tool?
10
The x component of vector A is 8.7 units and its y component is -6.5 units. The magnitude of vector A is closest to
11 units
An object is being pushed along a horizontal surface by a force of 60 N with an acceleration of 4. The coefficient of kinetic friction between the object and the surface is 0.1, the mass of the object is most nearly
12
A 3 kg and a 5 kg box rest side by side on a smooth, level floor. A horizontal force of 32 N is applied to the 5 kg box pushing it against the 3 kg box and, as a result, both boxes slide along the floor. How hard do the two boxes push against each other?
12 N
A meter stick balances at the 50 cm mark. If a mass of 50g is placed at the 90 cm mark, the stick balances at the 61.3 cm mark. What is the mass of the meter stick?
127 g
A 200 N sled slides down a frictionless hillside that rises 37 degrees above the horizontal. What is the magnitude of the force that the surface of the hill exerts on the sled?
160 N
A boy jumps with a velocity of magnitude 20 m/s at an angle of 25 degrees above the horizontal. What is the horizontal component of the boy's velocity.
18.1 m/s
A girl throws a rock horizontally with a velocity of 10 m/s from a bridge. It falls 20 m to the water below. How far does the rock travel horizontally before striking the water, assuming negligible air resistance?
20
A jet plane is launched from a catapult on an aircraft carrier. In 2 s it reaches a speed of 42 m/s at the end of the catapult. Assuming the acceleration is constant, how far did ti travel during those 2 s?
42
What is the mass of an object that experiences a gravitational force of 685 N near Earth's surface where g=9.8?
69.9 kg
A 15 kg child is sitting on a playground teeter-totter 1.5 m from the pivot. What is the magnitude of the minimum force, applied 0.3 m on the other side of the pivot that is needed to make the child lift off the ground?
740 N
A runner ran the marathon (42 km) in 2 hrs and 57 mins. What was the average speed of the runner in m/s?
3.95
A mobile is shown in the figure. The horizontal supports have negligible mass. Assume that all the numbers given in the figure are accurate to two significant figures. What mass M is required to balance the mobile? (LOOK AT 8 ON TEST FOR PIC)
36 g
A 450 kg sports car accelerates from rest to 100 km/hr in 4.8 s. What magnitude force does a 68 kg passenger experience during the acceleration?
394 N
A bullet shot straight up returns to its starting point in 10 s. What is the initial speed of the bullet, assuming negligible air resistance?
49
A motorist makes a trip of 180 miles. For the first 90 miles she drives at a constant speed of 30 mph. At what constant speed must she drive the remaining distance if her average speed for the total trip is to be 40 mph?
60 mph
What must be your average speed in order to travel 350 km in 5.15 hr?
68
A 10 kg block on a frictionless horizontal table is connected by a horizontal string to a 63 kg block that is hanging over the edge of the table. What is the magnitude of the acceleration of the 10 kg block when the other block is gently released.
8.5
A motorist travels for 3 hr at 80 km/hr and 2 hr at 100 km/hr. What is her average speed for the trip?
88
A motorist travels 160 km at 80 km/hr and 160 km at 100 km/hr. What is the average speed of the motorist for this trip?
89
A uniform piece of medical apparatus that is 3.5 m long is suspended horizontally by two vertical wires at both ends. A small but dense 550N weight is placed on the apparatus 2 m from one end. What are the tensions, A (left) and B (right) in the two wires? (LOOK AT 6 ON TEST FOR PIC)
A = 910 N, B = 840 N
A certain test car can go from rest to 32 m/s in 3.88 s. The same car can come to full stop from that speed in 4.14 s. What is the ratio of the magnitude of the starting acceleration to the stopping acceleration?
NOT .878
Human reaction time is usually greater than 0.10 s. If your friend holds a ruler between your fingers and releases it without warning, how far can you expect the ruler to fall before you catch it, assuming negligible air resistance?
at least 4.9 cm
