A2150-kg truck is traveling along a straight, level road at a constant speed of 55.0 km/h when the driver removes his foot from the accelerator. after 21.0 s, the truck's speed is 33.0 km/h. what is the magnitude of the average net force acting on the truck during the 21.0 s interval?

624.5 N

Explanation:

m = mass of the truck = 2150 kg

v₀ = initial speed of the truck = 55 km/h = 15.3 m/s

v = final speed of the truck = 33 km/h = 9.2 m/s

t = time interval = 21 s

F = magnitude of the average net force

Using Impulse-Change in momentum equation

F t = m (v - v₀ )

F (21) = (2150) (9.2 - 15.3)

F = - 624.5 N

hence the magnitude of net force is 624.5 N

an obstruction

answer: the rock sample is a sedimentary rock.

explanation:

it is given that:

mass of rock sample, m = 2.7 g

volume of rock sample,

so, density of rock sample will be

since, the density of rock sample is . hence, the rock sample is a sedimentary rock, whose densities varies between .