The force needed to keep a car from skidding on a curve varies Inversely as the radius of the curve and jointly as the weight of th car's speed. Suppose that 200 pounds of force keeps a 3200 -pound car from skidding on a curve of radius 400 ft at 25 mph . What car from skidding on a curve of radius 550 ft at 55 mph ? pounds of force

travel at without slipping? A car travels at a constant speed in a circular path of 120 m radius. It completes one circuit in 23 s . If the ground is level, what is the minimum coefficient of friction between the tires and the road?

A bullet is fired at an angle of \( 30^{\circ} \) to the horizontal at a velocity of \( 400 \mathrm{~m} / \mathrm{s} \) Calculate the following: 1.2 .1 The maximum height reached by the bullet 1.2 .2 The horizontal displacement when the bullet hits the ground

Quesito 2A In un test d'urto, un'auto di massa \( \mathrm{m}=1500 \mathrm{~kg} \) urta contro un muro. La velocitá iniziale è \( \mathrm{v}_{\mathrm{i}}=15,0 \mathrm{~m} / \mathrm{s} \) e quella finale è \( \mathrm{v}_{\mathrm{r}}=2.60 \mathrm{~m} / \mathrm{s} \) con verso opposto. Se la durata dell'urto è \( 0,150 \mathrm{~s} \), determinare l'impulso dovuto all'urto e la forza esercitata sull'auto supposta costante.

The brightness of a light bulb changes inversely with resistance and directly with voltage. What is the new resistance if a 60 -watt, 120 -volt bulb is used in place of a 100 -watt, 120 -volt bulb with 144 ohms?

3) Se sabe que la aceleración (a) se define como el cambio de la velocidad \( (v) \) en el tiempo (t), entonces \( a=\frac{d}{d t} v \), si la velocidad en cierto sistema está determinada por: \( v(t)=t^{2}-5 t \) a) ¿Cuál será el tiempo en el cual la velocidad es constante? \( v(t)=-S \)