A box sitting on a horizontal surface is attached to a second box sitting on an inclined ramp by a rope that passes over an ideal pulley. The rope exerts a tension force T on both weights along the direction of the rope, and the coefficient of friction between the surface and boxes is 0.4 . If the box on the right weighs 100 pounds and the angle of the ramp is \( 36^{\circ} \), how much must the box on the left weigh for the system to be in static equilibrium? The box on the left must weigh approximately (Do not round until the final answer. Then round to two decimal places as needed.)

Answer True or False. 1. In motion means moving. 2. Scientists do not use a frame of reference to talk about motion. 3. You cannot tell whether an object is in motion unless you have frame of reference. 4. A frame of reference is some other object to which you compar an object's position. 5. When scientists study the motion of stars in the sky, they use clouds as a frame of reference.

1. A ciarge of \( 2 \mu \mathrm{C} \) is placed 0.1 m away from another charge of \( -3 \mu \mathrm{C} \). Using Coulomb's law. calculate the force between them. (Assume \( \left.k=8.99 \times 10^{9} \mathrm{~N} \mathrm{~m}^{2} / \mathrm{C}^{2}\right)(5 \mathrm{Marks} \) ) Calculate the electric field at a point where a \( 5 \mu \mathrm{C} \) charge experiences a force of 0.2 N . ( 5 Marks) An 1 C voltage of \( V(t)=220 \sin (100 \pi t) \) is applied to a \( 50 \Omega \) resistor. Calculate the pecie current through the resistor. ( 5 Marks) A capacitor with a capacitance of \( 20 \mu \mathrm{~F} \) is connected in an AC circuit with a frequency of 50 Hz . Calculate the capacitive reactance. ( 5 Marks )

1. If you were to visit a planet that was much more massive than earth, your mass would be a) More b) Less c) The same d) Impossible to tell without knowing which planet you are visiting. 2. Which of the following is not a form of light? a) radio waves b) microwaves c) x-rays d) All of the above are a form of light. e) None of the above is a form of light

A box sitting on a horizontal surface is attached to a second box sitting on an inclined ramp by a rope that passes over an ideal pulley. The rope exerts a tension force I on both weights along the direction of the rope, and the coefficient of friction between the surface and boxes is 0.6 . If the box on the right weighs 100 pounds and the angle of the ramp is \( 35^{\circ} \), how much must the box on the left weigh for the system to be in static equilibrium? The box on the left must weigh approximately \( \square \) pounds for the system to be in static equilibrium. (Do not round until the final answer. Then round to two decimal places as needed.)

Item 21. Uma bola é largada do alto de um edificio e cai em direção ao solo. Sua altura \( h \) em relação ao solo, \( t \) segundos após o lançamento, é dada pela expressăo \( h=-20 t^{2}+ \) 3380. Após quantos segundos do lançamento, a bola atingirá o solo \( (h=0) \) ?