As shown in figure, a $70\,kg$ garden roller is pushed with a force of $\overrightarrow{ F }=200\,N$ at an angle of $30^{\circ}$ with horizontal. The normal reaction on the roller is $.......\,N$ $\left(\right.$ Given $\left.g =10\,m s ^{-2}\right)$

Two masses of $10 \,kg$ and $20 \,kg$ respectivety are connected by a massless spring as shown in fig. A force of $200 \,N$ acts on the $20 \,kg$ mass At the instant shown the $10 \,kg$ mass has acceleration $12 \,m / s ^2$ towards right. The acceleration of $20 \,kg$ mass at this instant is ........ $m / s ^2$

A block of $\sqrt{3}\,kg$ is attached to a string whose other end is attached to the wall. An unknown force $F$ is applied so that the string makes an angle of $30^{\circ}$ with the wall. The tension $T$ is $...........\,N$ :(Given $g =10\,ms ^{-2}$ )

A pebble of mass $0.05\; kg$ is thrown vertically upwards. Give the direction and magnitude of the net force on the pebble,

$(a)$ during its upward motion,

$(b)$ during its downward motion,

$(c)$ at the highest point where it is momentarily at rest.

Do your answers change if the pebble was thrown at an angle of $45^o$ with the horizontal direction? Ignore air resistance.

Which of the following is the correct order of forces

A car accelerates on a horizontal road due to the forces exerted by