Electric field intensity at a point on the a line of an electric dipole.

3. You cannot tell whether an object is in motion unless you ha frame of reference. 4. A frame of reference is some other object to which you comp an object's position. 5. When scientists study the motion of stars in the sky, they use clouds as a frame of reference.

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.

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.)

Uno ascensor y su carga pesan 12000 N . Si sube desde una planta baja hasta un quinto piso situado a 12 m de altura en un tiempo de dos minutos; calcula en referencia al motor que acciona la carga, el trabajo realizado durante la maniobra. (ANOTA EL RESULTADO PORQUE QUIZÁS LO NECESITARÁS PARA HACER LAS CUESTIONES 14 Y 15) RECUERDA NO PONER LAS UNIDADES, SÓLO EL NÚMERO. TAMPOCO PUEDES PONER LOS PUNTOS EN LOS MILLERS (POR EJEMPLO CINCUENTA MIL NO LO PUEDES PONER COMO 50.000, HAY QUE PONER 50000), LOS DECIMALES LOS TIENES QUE PONER CON UNA COMA ABAJO: EJEMPLO 3,5

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 \( (h=0) \) ?