Physics Home work(due in 1 hr)
faisal.kanwan
physhw5.docxHOMEWORK
1) A 980 kg car is pulling a 315 kg trailer. Together the car and trailer move forward with an acceleration of 2.25 m/s2. Ignore any frictional force of air drag on the car and all frictional forces on the trailer.
(a) Determine the net force on the car.
magnitude = N
direction=
(b) Determine the net force on the trailer.
Magnitude= N
Direction=
(c) Determine the force exerted by the trailer on the car.
Magnitude= N
Direction=
(d) Determine the resultant force exerted by the car on the road. (Assume that the forward direction is along the +x-direction.)
magnitude= N
direction= ° (measured from the left of the −y-direction)
2)
A bag of cement weighing 250 N hangs in equilibrium from three wires as suggested in the figure below. Two of the wires make angles θ1 = 64.0° and θ2 = 45.0° with the horizontal. Assuming the system is in equilibrium, find the tensions T1, T2, and T3 in the wires.
|
T1= |
N |
|
T2= |
N |
|
T3= |
N |
3) Two objects are connected by a light string that passes over a frictionless pulley as shown in the figure below. Assume the incline is frictionless and take m1 = 2.00 kg, m2 = 6.90 kg, and θ = 56.5°.
(a) Draw free-body diagrams of both objects.
(b) Find the magnitude of the accelerations of the objects.= m/s2
(c) Find the tension in the string.= N
(d) Find the speed of each object 1.25 s after being released from rest. = m/s
4) Two blocks, each of mass m = 3.00 kg are hung from the ceiling of an elevator as in the figure below.
(a) If the elevator moves with an upward acceleration of magnitude 1.5 m/s2, find the tensions T1 and T2 in the upper and lower strings.
T1 = N
T2 = N
(b) If the strings can withstand a maximum tension of 71.9 N, what maximum acceleration can the elevator have before a string breaks?= m/s2
5) A 8.80-kg hanging object is connected by a light, inextensible cord over a light, frictionless pulley to a 5.00-kg block that is sliding on a flat table. Taking the coefficient of kinetic friction as 0.220, find the tension in the string.
= N
6) A coin placed 30.4 cm from the center of a rotating, horizontal turntable slips when its speed is 49.0 cm/s.
(a) What force causes the centripetal acceleration when the coin is stationary relative to the turntable?(choose)
· static friction
· inertia
· kinetic friction
· centrifugal force
(b) What is the coefficient of static friction between coin and turntable?
7) A 39.0-kg child swings in a swing supported by two chains, each 3.10 m long. The tension in each chain at the lowest point is 352 N.
(a) Find the child's speed at the lowest point.
= m/s
(b) Find the force exerted by the seat on the child at the lowest point. (Ignore the mass of the seat.)
= N (upward)
