6. Intro to Forces (Dynamics)

A man pushes on a piano with mass $180$ kg; it slides at constant velocity down a ramp that is inclined at $19.0°$ above the horizontal floor. Neglect any friction acting on the piano. Calculate the magnitude of the force applied by the man if he pushes parallel to the floor.

Which of the following scenarios is most likely to result in a head-on collision involving forces in two dimensions when passing another vehicle on a two-lane road?

Which of the following statements about blind spots and vehicle size is correct?

The position of a 2.0 kg mass is given by x = (2t³ - 3t²) where t is in seconds. What is the net horizontal force on the mass at t = 1s?

Which of the following force diagrams accurately represents the forces acting on a satellite in a stable circular orbit around $Earth$?

A trunk is being pushed leftward across a floor by three forces: a force of $300N$ to the left, a force of $200N$ to the right, and a downward force of $500N$. What is the magnitude of the net force acting on the trunk?

In a coordinate system where the $x$-axis is aligned along an inclined plane and the $y$-axis is perpendicular to the plane, which of the following forces always lie along the coordinate axes for an object resting on the plane?

A $5.00$-kg crate is suspended from the end of a short vertical rope of negligible mass. An upward force $F\left(t\right)$ is applied to the end of the rope, and the height of the crate above its initial position is given by $y\left(t\right)=$ ($2.80$ m/s)t + ($0.610$ m/s³)t³. What is the magnitude of $F$ when $t=4.00$ s?

Two forces of equal magnitude are applied at the end of a screw eye to remove a post. If the forces are applied at an angle of $120°$ to each other, what is the magnitude of the resultant force in terms of the magnitude $F$ of each force?

Andrea dangles her watch from a thin piece of string while the jetliner she is in accelerates for takeoff, which takes about 21 s. Estimate the takeoff speed of the aircraft if the string makes an angle of 24° with respect to the vertical, Fig. 4–61.

A 2.0 kg projectile with initial velocity v = 8.0 î m/s experiences the variable force F = -2.0t î + 4.0t² ĵ N, where t is in s. What is the projectile's speed at t = 2.0 s?

(II) Two large snowcats are towing a housing unit north, as shown in Fig. 4–42. The sum of the forces ${\overrightarrow{F}}_A$ and ${\overrightarrow{F}}_B$ exerted on the unit by the horizontal cables is north, parallel to the line $L$, and ${\overrightarrow{F}}_A=4200\text{ N}$. Determine ${\overrightarrow{F}}_B$ and the magnitude of ${\overrightarrow{F}}_A+{\overrightarrow{F}}_B$.

You push a 5.1kg cart along the floor with an unknown force F at 30° below the horizontal. Using a scale, you know the Normal force is 70N. What is the horizontal acceleration of the cart?