Answer:
32 m and -2.4 m/s
Explanation:
Given:
v₀ = 25 m/s
t = 2.8 s
a = -9.8 m/s²
Find: Δy, v
Δy = v₀ t + ½ at²
Δy = (25 m/s) (2.8 s) + ½ (-9.8 m/s²) (2.8 s)²
Δy = 31.6 m
v = at + v₀
v = (-9.8 m/s²) (2.8 s) + 25 m/s
v = -2.44 m/s
Rounded to two significant figures, the bullet reaches a height of 32 m and a velocity of -2.4 m/s.
Answer:
because thermometric liquid readily expands on heating or contracts on cooling even for a small difference in the temperature of the body.
Answer:
B.The force of friction between the block and surface will decrease.
Explanation:
The force of friction is given by
where 
is the coefficient of friction and 
is the normal force.
When the student pulls on the block with force 
at an angle 
, the normal force on the block becomes
and hence the frictional force becomes
.
Now, as we increase , 
increases which as a result decreases the normal force 
, which also means the frictional force decreases; Hence choice B stands true.
<em>P.S: Choice D is tempting but incorrect since the weight </em>
<em> is independent of the external forces on the block. </em>
Answer:
Cools ; size
Explanation:
The rate at which magma cools determines the size of the crystals in the new rock. Igneous rocks are formed from the cooling and solidification of molten magma which finds its way to the surface or depth of very low pressure beneath the surface. This place or depth of cooling of magma affects the cooling rate and hence the size of the crystals formed. Igneous rocks formed at depths below the surface have more time to cool and allows more time for Crystal growth and hence produce coarse grained crystal grains called Intrusive igneous rocks which have significantly larger crystals than those formed on the surface which cools rapidly and allowing very little time for crystal growth giving rise to the formation of fine grained crystals and are called extrusive igneous rocks.
