SOLVE
A swimmer is capable of swimming 0.60 m/s in still water. The swimmer aims her body directly across a 48 m wide river whose current is 0.40 m/s.
What is the magnitude and direction of the velocity of the swimmer with respect to an observer on shore?
What is...
0.72 m/s
Theta = 33.69
Above the positive x.
What are the two dimensions of kinematics?
Projectile motion and Relative Velocity
According to Newton's laws of motion, define net force.
Net force is the vector sum of all the forces acting on an object.
A 25-kg crate is on a surface that is inclined above the horizontal at an angle theta. The coefficient of static friction between the crate and the incline is 0.35. What is the maximum angle theta that causes the crate to be just about to slide?
19.3 degrees
A low-friction cart starts from rest and is pushed by a small plunger, causing it to accelerate at 0.800 m/s per second for 4.00 s across a horizontal platform.
At the end of the platform, the cart leaves the edge and falls to the ground below, which is 6.00 m lower than the platform. Ignore air resistance.
Determine the amount of time the cart is in the air.
t = 1.1063
A student is standing on a scale in an elevator that is moving downward and accelerating. The scale reading is:
a) Greater than the true weight of the student
b) could be greater or smaller depending upon the value of the acceleration
c) None of these
d) Less than the true weight of the student
e) Equal to the true weight of the student
D
What is Newtons first law?
An object at rest stays at rest.
An object in motion at constant velocity stays in motion.
In the figure, we see two blocks connected by a string and tied to a wall, with theta = 33.0 degrees. The mass of the lower block is m = 1.45 kg; the mass of the upper block is 3.00 kg. Find the tension in the string that is tied to the wall.
26.2N
A 9.20 kg duffel bag is being pulled across an airport floor by a traveler using a strap that exerts a force of 52.0 N at an angle of 35.0 degrees above the horizontal. The coefficient of kinetic friction between the duffel bag and the floor is 0.180.
What are the algebraic expressions for the normal force (FN) and the acceleration of the backpack?
a= Fcostheta - Mx(Mg - Fsintheta)/m
What is friction? And give me the two types of friction.
Contact force that opposes the relative motion of two surfaces as they slide past each other.
Types: Static friction and Kinetic Friction
What is Newton's second law?
An object in motion when the net force does not equal zero.
Net force causes an object to accelerate or decelerate.
A projectile is fired with a speed of 60m/s at angle of 30 degrees with the horizontal. What is the speed at the highest point it reaches?
a) 43m/s
b) 0m/s
c) 52m/s
d) 30m/s
e) 60m/s
C
Assuming that the orbit was circular and the vehicleis 110 km above the lunar surface. If the mass is 7.35x1022 kg and r = 1.74 x106m, determine
a) orbital speed of the spacecraft
b) period of the moon
a) v = 1.63x103m/s
b) 7.12x103s
In an experiment with a block of wood on an inclined plane, the following observations are made: (1) If the block is placed on the inclined plane, it remains there at rest. (2) If the block is given a small push, it accelerates towards the bottom without any further pushing. What conclusion can be drawn from these observations?
a) The coefficient of kinetic friction must be negative
b) The coefficients of kinetic friction and static frition are equal
c) The coefficient of kinetic friction is larger than the coefficient of static friction.
d) The coefficient of static friction is larger than the coefficient of kinetic friction.
e) The coefficient of static friction is zero; the coefficient of kinetic friction is non-zero.
What is Newton's third law?
A box is placed on the floor at the edge of a merry-go-round of radius 6.0m. my between the box is 0.30m. Determine the tangential speed of the merry-go-round so the box does not slide off.
v=4.2 m/s
A box of mass m = 5.0 kg, initially at rest, is being pulled along a smooth horizontal surface by a rope that makes an angle of 30 degrees with the horizontal and exerts a force of 20N on the box. Determine the
a) Free-body diagram
b) Newton's Second Law
c) Find the components
d) Use algebra to solve
a)
b) F + FN +mg = ma
c) x:+Fcostheta +0+0 = ma
y:+Fsintheta + FN-mg = 0
d) a = 3.5m/s2
FN = 39N