A 1200 kg car pushes a 2200 kg truck that has a dead battery . When the driver stes on he accelerator, the drive wheels of the car push against the ground with force of 4000N. Rolling friction ca be neglected.

(a) What is the magnitude of the force of the car on the truck?
Express you answer to two significant figures and include the appropriate units.
(b) What is the magitude of the force of the truck on the car?
Express your answer to two significant figures and include the appropriate units.

Which best represents the law of conservation of mass ?

The frequency of vibrations of a vibrating violin string is given by f = 1 2l t ρ where l is the length of the string, t is its tension, and ρ is its linear density.† (a) find the rate of change of the frequency with respect to the following. (i) the length (when t and ρ are constant) (ii) the tension (when l and ρ are constant) (iii) the linear density (when l and t are constant) (b) the pitch of a note (how high or low the note sounds) is determined by the frequency f. (the higher the frequency, the higher the pitch.) use the signs of the derivatives in part (a) to determine what happens to the pitch of a note for the following. (i) when the effective length of a string is decreased by placing a finger on the string so a shorter portion of the string vibrates df dl 0 and l is ⇒ f is ⇒ (ii) when the tension is increased by turning a tuning peg df dt 0 and t is ⇒ f is ⇒ (iii) when the linear density is increased by switching to another string df dρ 0 and ρ is ⇒ f is ⇒

Sort the images based on whether there's a force of attraction or repulsion between the magnets shown. attraction repulsion