6. Intro to Forces (Dynamics)

A picture frame hung against a wall is suspended by two wires attached to its upper corners. If the two wires make the same angle with the vertical, what must this angle be if the tension in each wire is equal to $0.75$ of the weight of the frame? (Ignore any friction between the wall and the picture frame.)

Which type of equilibrium is observed when a ball is placed at the bottom of a hemispherical bowl?

When a mass of 25 kg is hung from the middle of a fixed straight aluminum wire, the wire sags to make an angle of 12° with the horizontal as shown in Fig. 12–90. Determine the radius of the wire.

In an electricity experiment, a 1.0 g plastic ball is suspended on a 60-cm-long string and given an electric charge. A charged rod brought near the ball exerts a horizontal electrical force F_electric on it, causing the ball to swing out to a 20° angle and remain there. What is the magnitude of F_electric?

A $1130$-kg car is held in place by a light cable on a very smooth (frictionless) ramp (Fig. E$5.8$). The cable makes an angle of $31.0°$ above the surface of the ramp, and the ramp itself rises at $25.0°$ above the horizontal. Find the tension in the cable.

The two trees in Fig. 12–54 are 6.2 m apart. A backpacker is trying to lift his pack out of the reach of bears. Calculate the magnitude of the force $\overrightarrow{F}$ that he must exert downward to hold a 19-kg backpack so that the rope sags at its midpoint by 0.15 m.

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A chandelier is supported from the ceiling by 2 chains. Both chains make a 30° angle with the vertical. The tension in each chain is the same because of symmetry:T₁=T₂=50 N. What is the mass of the chandelier?

A sphere hangs suspended by a light string, resting against a vertical wall. The sphere has a mass of 2 kg and the string makes an 80° angle with the horizontal. What is the force from the wall against the ball?

The three ropes in FIGURE EX6.1 are tied to a small, very light ring. Two of these ropes are anchored to walls at right angles with the tensions shown in the figure. What are the magnitude and direction of the tension T3 in the third rope?