Exam 3: Kinematics in Two Dimensions; Vectors

Two forces are acting on an object as shown in the figure. Assume that all the quantities shown are accurate to three significant figures. (a) What is the magnitude of the resultant force on the object? (b) What is the direction of the resultant force?

A 50-kg box is being pushed along a horizontal surface. The coefficient of static friction between the box and the ground is 0.65, and the coefficient of kinetic friction is 0.35. What horizontal force Must be exerted on the box for it to accelerate at 1.2 m/s²?

A projectile is fired from ground level with a speed of 150 m/s at an ang above the horizontal on an airless planet where g = 10.0 m/s². What is the horizontal component of its velocity after 4.0 S?

Vector has a magnitude of 7.0 m and points east of north. Vector has a magnitude of 5.0 m and points west of south. The resultant vector is given by

A child is trying to throw a ball over a fence. She gives the ball an initial speed of 8.0 m/s at an angle of ° above the horizontal. The ball leaves her hand 1.0 m above the ground and the fence is 2)0 m high. The ball just clears the fence while still traveling upwards and experiences no Significant air resistance. How far is the child from the fence?

A student adds two displacement vectors that have the magnitudes of 12.0 m and 5.0 m. What is the range of possible answers for the magnitude of the resultant vector?

The eastward component of vector is equal to the westward component of vector and their northward components are equal. Which one of the following statements must be correct for these two vectors?

A batter hits a home run in which the ball travels 110 m horizontally with no appreciable air resistance. If the ball left the bat at above the horizontal just above ground level, how fast was it hit?

Vector has a magnitude of m and points north of east; vector has a magnitude of m and points west of north; and vector has a magnitude of m and points west of south. The resultant vector is given by

The figure shows three vectors, having magnitudes 7.0 cm, 6.0 cm, and 4.0 cm, respectively. Find the x and y components of the resultant of these three vectors.

A boat, whose speed in still water is 8.0 m/s, crosses a river with a current of 6.0 m/s. If the boat heads perpendicular to the current, what is the speed of the boat relative to an observer standing On the shore as it crosses the river?

A boulder rolls off of a very high cliff and experiences no significant air resistance. While it is falling, its trajectory is never truly vertical.

At a location where g = 9.80 m/s², a projectile returns to its original height after 4.08 seconds, during which time it travels 76.2 meters horizontally. If air resistance can be neglected, what was the projectile's initial speed?

A person throws a ball horizontally from the top of a building that is 24.0 m above the ground level. The ball lands 100 m down range from the base of the building. What was the initial velocity Of the ball? Neglect air resistance and use g = 9.81 m/s².

A vector in the xy -plane has an x component of -7.50 units. What must be the y component of this vector so that its magnitude is 10.0 units. (Note: There are two possible answers.)

A football kicker is attempting a field goal from 44 m out. The ball is kicked and just clears the lower bar with a time of flight of 2.9 s. If the angle of the kick wa , what was the initial speed of The ball, assuming no air resistance?

For general projectile motion with no air resistance, the horizontal component of a projectile's velocity

A projectile is fired from ground level on a horizontal plain. If the initial speed of the projectile is now doubled, and we neglect air resistance,

A plane has an eastward heading with an airspeed of 156 m/s. A 20.0 m/s wind is blowing southward at the same time as the plane is flying. The velocity of the plane relative to the ground is

Three forces, each of magnitude 70 \mathrm{~N} , all act on an object as shown in the figure. The magnitude of the resultant force acting on the object is