Answer:
write something like after the spacecraft launched all of the potential energy transformed into kinetic energy causing the spacecraft to go at an abnormal spped.
Explanation:
S = 10 + (-4) = 6
Displacement is vector quantity
Answer:
4 m/s in negative acceleration
Explanation:
Acceleration = V- U/t
Where V is the final velocity
U is the initial velocity and t is the time given.
U = 65 m/s
V= 25 m/s
T= 10 seconds
Acceleration= (25m/s - 65m/s)÷10secs
= - 40/10
= -4m/s^2
Hence, it has a negative acceleration.
Answer: Force = Mass X Acceleration
F = 5 x 2
F = 10 N
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>
